Crusader Kings is a historical grand Turn-Based Strategy / Real Time Strategy4X game produced and published by Paradox Interactive. It's set chronologically before its sister series, Europa Universalis, and uses a variant of the Europa Universalis II engine.The game was originally developed by Snowball, who abandoned it in a very unfinished state, forcing Paradox to do some last-minute fixes before release, this makes the game exceedingly buggy and all but unplayable in its post-release state. Some furious activity both by the community (via modding) and Paradox Interactive itself (via both patching and the Deus Vult expansion) has rendered the game significantly more stable and fixed many of the gameplay mechanics.The gameplay itself is somewhat original in concept: Rather than playing a particular nation you play as a dynasty (with direct control being vested in the head of said dynasty) in medieval Europe starting in 1066 (or 867, as of The Old Gods) and ending in the early 1400's. While you can raise armies, form alliances and so forth the most important aspect of the game is management of your family and estates: The amount of land you can directly control is limited by certain factors, and thus you have to parcel out land to your vassals. These vassals have their own personality traits and ideas (some of them which makes them butt heads with you... Or each other) The focus on individual characters and the dynamics within your dynasty gives the game a quality that is almost The Sims-like. It's also notable for being one of the first Paradox Interactive games to rely on Random Events with complicated triggers rather than chains of Scripted Events to drive the game, which would go on to become the staple of the company's later games.A sequel, Crusader Kings II, was released on February 14th 2012, and a demo has also been released. Amongst other gameplay changes, the sequel introduces character ambitions, an expanded plotting and intrigue mechanic, a revamp of the holy order and mercenary system and the sub-division of provinces into baronies, bishoprics and cities, all ruled by vassals.Paradox has released numerous expansion packs for the game, each focusing on different aspects:
Sword of Islam, released in June 2012, expands the maps, introduces new mechanics, and features playable Muslims, with different rules to reflect their different culture.
The Republic, released in January 2013, makes republics playable and adds mechanics to simulate patrician families and republican elections.
The Old Gods, released in May 2013, makes Pagans and Zoroastrians playable, gives them unique events and mechanics, and adds another start date in 867 AD.
Sons of Abraham, released in November 2013, which focuses onChristianity, Islam, andJudaism, most notably adding the Jewish Khazar dynasty into the campaign maps and including the College of Cardinals for papal elections.
Rajas of India, set for a spring 2014 release, set to expand the map eastward to include India and much of Central Asia. It adds three new religions (Hinduism, Buddhism, and Jainism), Jungle terrain, new events and mechanics to account for Indian cultural and religious beliefs, and war elephants. Some additional content for the East African Miaphysite kingdoms that was originally intended to be part of its own expansion will also come at the same time, added with the free update to the base game scheduled to come at the same time as the new DLC.
A Child Shall Lead Them: Especially if the heir of the realm is under 16; Larger realms will feel the pressure especially for younger leaders, as they have low stats (which do grow as the ruler gets older).
Furthermore, being subject to an underage ruler is cause for yet another loyalty hit for one's vassals.
Not as bad in the sequel, where underage or otherwise incapable-to-rule leaders will be appointed a regent to rule in their stead. However, this introduces new problems.
Aerith and Bob: A character's given name is determined by their culture, not that of their parents. A character usually inherits his father's culture, but has a small chance of either inheriting his mother's or identifying with that of the home province of the capital. This can lead to such oddities as a Christian crusader kingdom being led by a Catholic "King Muhammad."
Affably Evil: The game gives bonuses for virtuous traits, such as being kind, humble, or charitable. However, having these traits does nothing to stop you from ordering the murder of children or amassing territory through brutal conquest. The trait-modelling system itself can occasionally cough up a charitable, soft-spoken young man whose chief hobby is impaling people on stakes.
All National Origin Myths Are True: Just about every ruler of dubious historicity and every distant dynastic connection only attested in sources written centuries after the fact is given the benefit of the doubt and represented in the game.
For Example, ninth-century Lithuania is ruled by the Palemonids, most Irish counts are linked to Conn of the Hundred Battles, the future kings of Sweden are said to be descended from the legendary Viking Ragnar Lodbrok, and the Arpad kings of Hungary are presented as relatives of the Khans of Old Great Bulgaria. Justified by the fact that the lack of sources in most of these cases means that the alternative is just making people up entirely, and that in the eras covered, the people involved did take such claims seriously.
Anachronism Stew: Mostly averted except for when game mechanics require the use of anachronistic terms. The most obvious example is the cultures mechanic, which, for example, differentiates between "Castillian" and "Portuguese" cultures. Such distinctions were not so obvious during the game's timeframe (even after the foundation of the Kingdom of Portugal as a separate entity from Spanish Castille and Leon) and cultural-linguistic similarities between the two cultures exist in Galicia until this very day. The fact that the game covers six centuries, significant portions of three continents, and multiple culture groups means that many things are simplified out of necessity compared to how they worked in the real world.
In the second games, the images for holdings, such as castles and cities, varies only based on religion, not time period. So you have stone castles for Catholic rules in 867 and Norse rulers still using wooden forts in 1400.
Apocalyptic Log: The title history for unstable kingdoms can come off as this, with the title going from legitimate king to powerful duke to pretender and back again over the course of a few years.
The map itself can come across as this, depending on your point of view. It can be very unnerving to see religious enemies or the Mongol hordes painting the map as they advance towards you.
Arranged Marriage: A huge part of the games is marrying off your children to the right people (while arranging a few deaths on the way) so that your heirs can inherit. A variety of systems of inheritance makes this a bit more complicated than it might seem.
The sequel places even more emphasis on making good marriages by folding the alliance system into the marriage system.
Perfectly Arranged Marriage: For the second game, the random event "You have fallen in love with your wife." may appear, giving you and your wife a +100 opinion bonus to each other.
Badass Preacher: Like other rulers, holders of religious holdings can lead troops into combat.
Bastard Bastard: There's a sequence of events by which a bastard son of your ruler might try to take his revenge for not being part of the inheritance. This stands a good chance of killing or at least maiming the victim.
Bi the Way: An inversion from the typical presentation — Homosexual characters can and will still marry and have children.
This is likely less an indicator of a character's bisexuality as it is an indicator of the stigma of homosexuality in medieval times. The homosexual character may have no attraction to the opposite sex, but they are still under tremendous pressure by a homophobic Church and relatives who want more heirs. In contrast, a combination of the "Homosexual" and "Lustful" traits results in a Fertility stat higher than that of a character with neither trait, and may in fact represent actual bisexuality.
Alternatively, a ruler without children is a bad ruler. Not because homosexuals are bad, but because no children will mean a Succession Crisis and that means war. So even if you were gay you had better close your eyes and think of England if you had any sense of responsibility. Same goes for dynastic marriages designed to unify or pacify to feuding families. If there are no children of mixed blood the feud might even become worse.
The plot mechanic introduced in the sequel means everyone is plotting against everyone. that includes heirs, wives and brothers-in-law all attempting to stab you in the back simultaneously. If you're not the plotting type, your poor king can sometimes come across as the Only Sane Man in a cast of psychopaths.
The Sword of Islam expansion compounds on this by allowing up to four marriages for Muslim rulers (and punishing powerful rulers who have less than four marriages), all of which can produce legitimate children. This means a lot of plotting by wives trying to maneuver their own child into becoming heirs. Another notable addition is the decadence mechanic for Muslim dynasties, which causes problems for dynasties with unlanded males. The only things worse than plotting family members are plotting family members with land and armies...and family members who disgrace their family name by sitting around the palace drinking and chasing servant girls.
Black Dude Dies First: The Kingdom of Nubia is playable in the first game, an Orthodox one-province kingdom on the borders of the Fatimid Caliphate. It is incredibly doomed. The sequel extends the map farther south and adds the Duchy of Axum and Kingdom of Abyssinia, which are only slightly less doomed.
Mali and Songhai to the west, however, usually survive.
Brother-Sister Incest: The "You have fallen in love with X character" event does not check if said character is a family member...
As noted below, a patch for the sequel added the "Divine Blood" parameter specifically to model this for the benefit of modders and for characters worshipping Zoroastrianism.
Buy Them Off: Sometimes, the Pope will offer forgiveness of certain sins in exchange for a substantial cash donation to the Catholic Church. In a more general sense, you can buy indulgences to provide small boosts to your character's piety. You can also do this if the Pope demands that you switch to Papal Investiture without angering him further.
Cain and Abel: Really, it's more a question of which brothers won't try to kill you for the inheritance.
The Caligula: It's perfectly possible to have one of these leading your dynasty, sometimes at your discretion and sometimes... not.
In a nod to the historical Caligula, rulers with the "Lunatic" trait in the sequel can, among other things, appoint their horse to important council positions.
Church Militant: Crusader Kings has the crusading Holy Orders appear as states after Catholics take control of provinces in their particular areas of concern (they demand a province from whoever gets there first). Crusader Kings II has them appear as (effectively) mercenaries, whom you hire with Piety instead of Gold and who are only available when fighting infidels. They refuse to attack co-religionists.
With the new Sons of Abraham expansion for the sequel, they are once again independent states, and can be a lot more important. Donating money to them gives piety, but you can take a loan as well. Occasionally they make requests for courtiers to join their orders or the rights to build castles in your territory, and its hard to refuse if you haven't paid the debt. If they get too powerful, banishment is an option, but does NOT reflect well on your character's reputation.
Churchgoing Villain: Any character who has the Zealous trait on top of any number of interesting combinations of decidedly non-virtuous traits can be this, regardless of what faith they belong to.
The Clan: One key difference between these games and other grand strategy games is that, rather than managing a country or political faction, the player essentially manages a dynasty and its estates. You can lose almost everything you own and be forced to swear allegiance to another overlord, but as long as you have one county and a suitable heir to pass it along to, you're still in the game and still capable of recovering your lost realm — or forging a new one entirely — one way or another.
Dangerous Sixteenth Birthday: Sixteen is the age at which characters become adults. This makes them available for marriage proposals, government positions, and (in the case of males) leadership of armies, as well as when rulers (are supposed to) begin to rule in their own right as opposed to through a regency council.
Dark Messiah: Schizophrenic characters can become convinced that they are Christ Returned, which leads to them getting labelled as heretics. Heretics tend to get excommunicated one way or another; if they happen to be rulers, this allows other rulers to claim their titles much easier. This (and the inevitable loyalty hit the vassals get) often develops into an ever-worsening cycle of civil war, violence and general mayhem that only ends with the death of the Messiah-King (sometimes).
One of the DLCs for the second game, Sword Of Islam, actually turns this trope into a game mechanic - each Muslim dynasty has a decadence score, and having unlanded males of your dynasty sitting in your palace being idle, boozing and whoring makes your entire family look bad and invites more righteous dynasties to overthrow you.
Played straight by peasant revolts and adventurer invasions; kill or capture the leader, it's curtains for the rebel scum.
Subverted with noble rebellions. If the faction leader or the claimant to the throne is killed, the rebellion indeed ends, but the situation returns to the status quo ante bellum, and the lords who joined the rebellion still have their armies and the ability to rebel again (which often takes less than a year). By contrast, if the rebellion is defeated or forced to white peace, the defeated lords are unlikely to try again (and can be freely imprisoned if they start factioning again).
Defeat Means Friendship: In the first game, you can beat someone around, disable them permanently, kill off their family, and invade their country, yet they tend to agree to your offers to join your army after being defeated. Flipping vassals is one of the principle means of destroying a rival kingdom.
The second game kills "vassal flipping" stone dead; you can't seize a vassal's territory by force without defeating their liege. However, with the Old Gods DLC, if you play as a pagan, you can choose an ambition to become king of X. You can then use the subjugation casus belli to conquer Kingdom X without the time penalty. Every count you defeat gets a +75 opinion modifier for basically having the crap beaten out of them.
Also in the second game, crushing a major revolt against your rule gives a (brief) relationship boost to all of your vassals, as they are suitably impressed or cowed into submission.
Department of Redundancy Department: "Sultan" is both a Muslim ruler title and a possible first name for Magrebi Arabs, certain cultures restyle the title name to match the dynasty name under an Islamic ruler, and randomly-generated Muslim dynasties take the name of their founder... which can result in Sultan Sultan I leading the Sultan Sultanate.
Disproportionate Retribution: Did the next count over look at you funny during the last banquet? Claim his titles, go to war, and strip him of everything he loves!
The addition of baronies and several preset courtiers in the sequel introduces even more famous families: the Romanovs begin as High Chiefs of the Samoyeds, the Hohenzollerns begin as the barons of Zollern and the Trastamaras (one of the royal families of Spain before the Habsburgs inherited the lot) begin as lowly courtiers in Galicia. Heck, even the Pushkins appear with a child courtier in Rostov.
Easy Logistics: Averted - Armies are EXPENSIVE, and you're strongly advised not to keep them mobilised when you're not at war. Large armies can also suffer attritional losses which can make entire stacks disappear if you don't manage them well.
Played straight by the Mongols, who never take attrition damage. This is a big part of why they're considered Demonic Spiders.
Crusader Kings II adds opinion penalties for having vassal levies raised too long.
With the 1.10 patch, low-tech pagan lands have very low supply. Therefore, a catholic army of 7000 can get reduced to 2000 or less in less than a year because the supply for the land is 800 with a castle garrison of 1200.
Elective Monarchy: Elective inheritance, along the lines of the Holy Roman Empire, is one option for succession in both games. In the sequel, it's a good way of keeping your vassals happy, but can be troublesome to have your chosen successor actually be the chosen successor.
The 1.09 patch added Tanistry, an alternative style of elective inheritance which limits the candidates to the sovereign's dynasty.
Elite Army / Zerg Rush: Both and somewhere in between. The time frame covered means that your levies are all conscripts and not professional soldiers (that'd be the mercenaries you can hire). Also comes into play with the Hordes as they can show up with close to a quarter million soldiers (with reinforcements on their heels).
There's also the Fatimid Caliphate and Seljuk Sultanate/Abbasid Caliphate which are comparable in power on the Muslim side.
With the release of Legacy of Rome, it's now possible for the Byzantine Empire to reform the original Roman Empire.
As of The Old Gods, you can now take direct control over the Mongols, whose leader on their historical appearance holds an Emperor-level title.
You can technically establish an empire at any time as long as you control a high enough percentage of its de jure territories and have the money and piety to pay for the title. There are even some "hypothetical" empires like Carpathia (Hunagary, Wallachia, & Bulgaria) and the Wendish Empire (Poland, Lithuania, Estonia, parts of Russia) that represent things that did not exist, but could, in theory, have.
The Emperor: "Emperor" is the highest-level title possible in the second game and is able to hold "mere" kings as vassals. Most of the empires listed above are led by such a figure, including the co-Trope Naming Byzantines and Holy Romans. Exactly what flavour of Emperor a character is depends on their stats and traits.
Enfant Terrible: A character is never too young to start gaining some very negative traits.
Evil Chancellor: A definite possibility, especially in the sequel, where they can easily be plotting to kill you and steal your title. If it's the Spymaster, who's responsible for finding out such plots, Heaven help you.
The Evil Prince: Almost certainly the player. It's that kind of game, really.
This tends to happen a lot more often in the sequel - if your ruler gives his heir a title, the heir will occasionally attempt to quicken his ascension. If a ruler has two sons and only one can inherit, expect a lot of murders to happen as both princes try to out-evil each other.
This becomes an even bigger problem in Sword of Islam - Muslim rulers need to make sure all their male relatives have lots of lands and armies or risk their dynasty appearing corrupt and decadent, which also means gives them much more ammunition for potential throne-stealing shenanigans.
Family Values Villain: A given for many characters, considering that half of the villainous things you'll do in a game will be to ensure your family prospers and stays in power.
Feudal Overlord: You and most of the characters you interact with. How closely any given character adheres to the negative stereotype is up to your own actions and those of the game engine.
For Want of a Nail: By contrast to the first game, the second game is built on the Europa Universalis III engine and shares its far less deterministic design philosophy. Naturally, this has a impact on historical events.
Founder of the Kingdom: Some historical kingdoms (Portugal, Finland, Ireland and Rus, for example) start the game fragmented into several independent duchies and counties or occupied by foreigners. Liberating enough provinces lets a character found their own kingdom.
The new start date introduced by The Old Gods in 867 splits up England, Denmark, Sweden, and Norway, among many others, and includes historical kingdom-founders Alfred The Great of England and Haraldr Fairhair of Norway.
Game-Breaking Bug: There's a bug that makes a siege reset upon the siege progression meter emptying, and it does this every time the siege "ends" meaning that you have to make your army physically leave the province and come back again, possibly killing off thousands of soldiers through attrition. If this happens your best bet is frankly to reload.
Genghis Gambit: If a state is being attacked in a Holy War, Invasion, Crusade or Jihad, its ruler gets a +30 "defending against infidels" relation bonus to all their vassals. Sometimes a well-timed defensive war can really bring quarrelling subjects under a single banner. Also, if a foreign ruler starts a war to claim Vassal X's title to his own realm, Vassal X will get a +100 "defending my title" bonus to his own liege for as long as the war lasts, which more or less ensures they will forsake all their rebellious intentions for that period.
The Good King: Taking actions that generally give piety, being fair and just, etc.
Gotta Catch Them All: You get a lot of prestige for every Duchy, Kingdom, and Empire title created and inherited, so there's an incentive to collect as many as possible. However, your vassals start to hate you if you have too many high-tier titles, especially Duchy titles.
Handicapped Badass: Getting maimed only reduces a general's Martial stat by 2, meaning that your best general will still remain a great asskicker even if they lose a limb or two.
Heir Club for Men: Enforced in the original, but Crusader Kings II allows you to loosen the restriction a little and even (if your characters belong to the Basque culture or Cathar heresy) adopt full gender equality in the succession. Also, the addition of matrilineal marriages means that a woman can inherit a title and pass it on to her children which count as a part of her own dynasty rather then the father's.
The game has female-preference succession laws, but they are only there for Game Mods, as there is no way to enact them in-game (and no-one starts with them.
Heroic Bastard: If a bastard son receives his own fiefdom and doesn't end up trying to kill his father, he may sometimes end up being legitimized on the strength of his rule.
Crusader Kings II allows you to deliberately legitimize your bastards even if they aren't particularly noteworthy.
Sons of Abraham further expands on heresies, both by providing unique game-mechanics (for instance, Catharism can have female bishops) and by allowing a heresy to become the mainstream (turning the old orthodoxy into a heresy) if it becomes dominant enough over the 'parent' — meaning that after a while the 'convert all of Europe to Catharism' game would turn from Cathar heresy spreading in the face of Catholic orthodoxy to Cathar orthodoxy spreading in the face of Catholic heresy...
Hilarity Ensues: The vast majority of event options that aren't either practical or malicious tend to be this. Sometimes the game comes up with rather hilarious juxtapositions of the former, too (such as the "Ruler Commits an Act of Cruelty" event triggering at the same time that one of your provinces discovers a new weapon... or goats).
Hot Consort: Your spouse can have the "attractive" trait. The actual appearance of the character can sometimes subvert this—they might appear to be very beautiful or handsome, but various traits they possess will make them repulsive to everyone.
Idle Rich: Pretty much any courtier with no real duties qualifies. Muslims in the second game need to avoid this so that their family doesn't look corrupt and decadent. If you don't have enough duties for all your relatives, there areotheroptions.
Incest Is Relative: Only Brother-Sister Incest and Parental Incest are explicitly forbidden by the game mechanics, and then only for marriage; the falling in love event doesn't check to see if the lover is a family member. Also, only blood relations are forbidden; a stepson can marry his mother. The "Inbred" trait that sometimes results from these unions is a large drop to all that character's stats, including fertility and health, so they're not likely to breed any further.
Some of the mechanics can still imply, for example, that your wife is having an affair with your son.
Justified to a degree; the middle ages wasn't as bothered by anything beyond incest between direct family members. Marriage within royal houses was a common tactic to consolidate feudal land.
The Zoroastrian rulers, enabled in "The Old Gods", are allowed to marry sisters, daughters, mothers and such, and in fact get a relation bonus to all their Zoroastrian vassals and 100 piety if they do so. Thankfully, they are allowed to keep concubines, to produce non-inbred inheritors.
In the Blood: Characters will pass onto their offspring a tendency to have similar stats. This was strong enough in earlier versions that a form of Darwinian evolution could be observed, where since characters with higher stats were more likely to survive and to succeed as rulers and pass their traits on, everyone in the late game had insanely high stats.
This was nerfed in the sequel; a genetic system still exists but there's a greater element of randomisation with regards to congenital/inheritable traits. Still, a eugenics-minded player can implement large-scale extensive breeding projects to produce the perfect heir.
It's Been Done: Bad luck could result in a province making a discovery, while the rest of the world has already moved on to better things.
Averted in the first game. The game assumes that any two characters of the opposite sex who are friends are actually lovers.
Crusader Kings II replaces friends and the loyalty meter with an unilateral (you can like someone who hates the very soil on which you stand) relationship meter. Romantic love remains as a separate modifier applied to the relationship.
Loyal to the Position: Even if they got their title by literally stabbing the guy in the back, your character usually inherits their benefactor's court along with their fiefdom.
The Many Deaths of You: There are many, many ways your characters can die. One of the more recent patches introduced a "cause of death" mechanic, and these tend to be strangely generic. Suicide is "Death by Depression", heart attacks are "Death by Stress", Death by Sex is "Died in an Accident", and so on. Deaths caused by plotting can be anything from simple poisoning to driving carriages over cliffs to vorpal pillows to something that can only be described as "death by exploding manure pile."
Mama's Baby, Papa's Maybe: Male rulers can choose to disavow any knowledge of their bastards, which effectively leaves said bastard fatherless (and possibly resentful).
Maybe Magic, Maybe Mundane: A number of events in both games are seen by the characters as explicitly supernatural or miraculous, but could have more plausible explanations.
The Middle Ages: Covers almost all of the threemajordivisions all the way up to the generally-accepted end date of 1453. Only the fifth through the middle ninth centuries AD aren't represented at present.
A Million is a Statistic: The game mechanics practically encourage this. Keeping your vassals' troops on the field starts to accumulate relationship penalties with them, while getting their armies slaughtered has no negative effects other than having to wait for more troops to be conscripted. Thus, once you get a big enough army to storm castles rather than waiting outside sieging them, you'll want to throw away a few thousand lives to save time.
The Missionary: Court chaplains can minister to heathen or heretic provinces within your realm, as well as to pagan courts in far lands, with a small chance of converting them to the faithful.
The Mistress: While love affairs are possible for Christians, concubines are common and expected among pagan and Zoroastrian rulers.
Moral Myopia: In order to attack a coreligionist, even if you're a king and he's a count, you need to have a claim on at least one of his titles. There's no such limitations for attacking heathens, though.
Mother Makes You King: Even with male-only inheritance laws, daughters get a claim on their father's titles, which they can pass on to their sons to press.
Non-Entity General: Sort of. You play as the current head of the Dynasty. If your King is overthrown and killed, you may get booted to your very distant cousin, who is a count of a backwater province, but your game WILL continue. The only way for the game to end is to have your dynasty die out in the male line.
In the sequel, you can have female heirs as a non-Muslim dynasty (eg the current head is not-Muslim) - if no males are eligible as heirs. You can, if you wish, choose to exclude females from being heirs, which may or may not be handy. But you can also give females equal rights to being heirs (but only for Basques or Cathars). With this option, as long as any one in your dynasty is alive, you can continue... though on the flip side, due to this being an era of Arranged Marriages, keeping females in the family without losing prestige can be... challenging.
Obvious Rule Patch: Every patch seems to alter gameplay in the direction posters on the Paradox Forums complain the most about. Such changes include having smaller peasant revolts, making it harder for counts to marry into ducal titles and Nerfing the Byzantines.
Offing the Offspring: If your heir is an Inadequate Inheritor, or has failed to produce a son with the aging Duke of Norfolk's daughter and only child, or just isn't in line for all the nifty titles your second son by another wife is, this is always an option.
The Pope: The Papacy is not playable, but the Pope can be a major asset if he is your friend, or a deadly threat if an enemy. Of course, if he gets too uppity you can always claim his provinces and remove the problem.
The sequel lets the player create anti-popes and even replace the pope if they're prestigious enough - and under certain circumstances, people have managed to have their character become Pope.
A rare few have had games where a character following a heretical form of Catholicism becomes pope... with the expected results (heretical religions such as Catharism start spreading while mainstream Catholicism dies out due to lack of moral authority.)
In Legacy of Rome, the Byzantine Empire or other Orthodox powers can reduce the Pope back to an ordinary Pentarch in a unified Orthodox Christianity, at which point Catholicism becomes heretical and the religious schism healed.
Properly Paranoid: The Paranoid trait grants a bonus to intrigue, meaning Paranoid characters are that much harder to assassinate if you actually are out to get them. This intrigue bonus is greater than the diplomacy penalty the trait gives, meaning that Paranoid is overall a beneficial trait.
Proud Warrior Race: Unreformed Norse and Tengri pagan rulers are required to fight wars regularly in order to maintain their stability. The latter group includes the much-feared Mongol hordes (as if they needed incentive enough).
Puppet State: Very strong element. The player is able to create vassals by giving the aristocrats in his court titles. Assuming relations are good enough he can force these vassals to raise troops for him and even force to them to surrender their title and land (though this is very likely to result in rebellion instead.)
It's also possible to press the claim of a dynasty member on a neighbouring country, since it takes several years to pacify the conquered regions the family member will then be almost completely dependent on you for support and the +100 relationship bonus means that the ruler will usually be an ally for life.
Put On An Ox Cart: Characters will sometimes retire or join a monastery; the game treats them for all purposes as though they'd died.
Crusader Kings II averts this; if the game says someone's dead, they are pushing up daisies.
Random Event: Unlike most other Paradox Interactive games, this game relies almost entirely on random events, with only a few historical occurrences (the arrival of the Mongols, plagues, founding of Holy Orders) having scripted events. This design philosophy would later influence the next generation of Paradox games (EU3, HoI3, V2) and would carry over with a vengeance in the sequel.
Relationship Values: A significant part of the gameplay, especially in the sequel. The first game had diplomatic relation scores between rulers, as well as a loyalty score between vassals and their lieges, the latter being essentially binary in practice. In Crusader Kings II, these were scrapped, and now every single character has a relationship value with every other character that is affected by a bewildering array of factors. Managing those scores is vital to both victory and survival.
Level-Up at Intimacy 5: If your vassals like you a lot, they'll provide you with far more troops and pay you far more in taxes than they're legally required to, be more likely to approve any legal reforms you want to push, and can even occasionally be persuaded to give up some of their lands to the crown, or even convert to your religion.
Removing the Rival: Really, this is the central trope to understanding how the game works. Every single character has his or her own agenda, and plans clash more often than not. You likely have to flatter, bribe, threaten, or murder an awful lot of people in order to get what you want and keep others from getting their hands on your stuff.
Revolving Door Revolution: Since new rulers always get a relationship penalty with their vassals (that gradually wears off as they maintain their hold on the throne), turnover time between rulers can be quite short indeed in kingdoms where no one ruler has enough power to hold out against a large enough faction (until someone eventually does or the kingdom itself splinters).
Rightful King Returns: Deposed rulers typically retain claims on their former thrones, which means that, just like any other claim holder, they can usurp it right back if they beat the current holder in a war.
Alternately, if your kingdom gets invaded and you get killed, your dynasty may fall to an heir who just happens to be out of the kingdom at the moment (probably leading an army somewhere), or even a remote relative on the other side of the continent. In either case, they'll hold a claim for the recently-seized throne, and may not have the political or military clout to take it back right away - resulting in this trope when they (or their descendants) finally DO return to claim the ancestral lands...
The Rival: Via random events characters may acquire rivals, with appropriate relationship penalties depending on your political relationship to each other. If one of your vassals is a rival of you, always be prepared for them turning on you, whatever their other traits or their loyalty. (They also get a nasty -3 to loyalty per month, meaning even quite loyal vassals can start sliding towards rebelllion.)
Royal Inbreeding: Many players practice this as an eugenics program, to get positive genetic traits into their dynasty. In the second game, Zoroastrians have all restrictions to marriage with close kin wiped away, and get bonuses to vassal relations and piety for incestuous marriages. To keep Zoroastrian families from descending into inbred messes, their men are allowed to keep three concubines for non-inbred but legitimate children, and the game code discreetly cheats by making inbred traits 75% less likely for children of Zoroastrian marriages.
Royally Screwed Up: This can happen, and when it does things get very interesting. And by interesting we mean civil wars and the attention of opportunistic neighbours.
Royals Who Actually Do Something: Most rulers generally lead, or at least fight with, their own armies. It's especially important for Muslim rulers to actually do something, or else they risk looking weak and decadent.
Ruling Couple: Can happen when one character has a spouse who is also a ruler in their own right.
Running Gag: One of the events that a character trying to improve his learning might get involves sighting a comet. "So it's not an ill omen."
Schizophrenic Difficulty: Even if you're the most powerful ruler in Europe in theory, the power that you actually wield pretty much correlates to how much your vassals like and respect you. A massive, map-spanning empire can crumble away in less than a decade when the underlings decide to take the throne for themselves or jump ship altogether.
Screw the Rules, I'm Beautiful!: The "attractive" trait gives a pretty big opinion bonus for any character who's sexually attracted to your gender. A beautiful queen can get away with a surprising amount of shit.
Self-Imposed Challenge: Kind of a given since the game is a Wide Open Sandbox with no set victory conditions. Among them is trying to recreate certain actual historical occurrences, trying to convert all of Europe to some minor spin-off of Catholicism such as Catharism, and simply choosing to play as a very weak country.
Crusader Kings II explicitly flags the deadly sins and heavenly virtues with numbered icons in red and green respectively.
She Is the King: While a secular female noble will have normal feminine titles, a female who is both a religious head and a countess/duchess (must receive the religious title first and requires Absolute Cognatic succession) will have the title of Prince-Bishop/Prince-Archbishop. If you then make her an Antipope, she'll become King-Bishop.
Simulation Game: The focus on dynastic politics means that you'll spend a lot of time tracking personal relationships and trying to groom your heirs to be good leaders.
Sketchy Successor: Another big threat. Having a poor leader who nonetheless can keep things stable isn't a big deal. Having a great king who was able to keep everyone in line, and then having him suddenly replaced by some blithering moron who seems to go out of his way to piss off his vassals and neighbors, can swiftly reduce a great empire to a series of warring duchies.
The Spymaster: You can appoint a vassal or courtier to serve as one, and a skilled one is an asset. You had better make damned sure they stay loyal to you, though, or they might become...
The Starscream: As mentioned below, disloyal vassals (particularly those with the Ambitious trait) are a bigger threat than almost anything outside your kingdom. Also, if the player character is anything less than a king, chances are the player themselves will be this. Characters with the "Realm Duress" trait will have all their vassals turn into The Starscream. Hilarity inevitably ensues.
Legacy Of Rome in the sequel makes it more severe: disloyal vassals will now form massive alliance chains with the sole objective of deposing you.
Succession Crisis: This and disloyal vassals are probably your greatest threats. Other kingdoms are a distant second, unless you're in the path of the Mongols...
Speaking of the Mongols, this is how they're kept in check. Mongols have all sorts of bonuses such as no demesne limit, no attrition, and the incredibly powerful horse archer unit, which allow them to rampage through Europe with impunity. The only thing stopping them is that when the Khan kicks the bucket, his enormous realm is divided among his male children (which tend to be a lot), who promptly start fighting amongst themselves, making them much more manageable. There's a much-hated random event that forces the player to institute a similar system of succession or take severe penalties. (And don't think you can cheat and immediately change it back; you can only change your succession laws every 25 years...)
The Imperial and Succession Laws of each Kingdom you rule in the sequel are tracked separately, leading to much potential succession trouble if you don't make their laws similar. There's also the Elective, Gavelkind, and Open succession laws, which are just asking for future wars.
Played straight in the sequel, where heirs that are second and third in line gain claims on the throne and become pretenders. If these pretenders are powerful and well-connected landholders, the realm can quickly dissolve into civil war. The myriad of alliances created through marriages can even drag powerful foreign realms into the crisis, creating a full-scale succession war, the likes of which become the stuff of history textbooks.
If nothing else, your vassals will often decide to revolt as soon as the new king is crowned, mostly because of the "short reign" relationship penalty, particularly if said ruler is a child/woman/both.
In Crusader Kings II, even happily married 40-year-olds with children can discover strange urges when attending a tournament.
There's even an event in Crusader Kings II where a demonic creature (implied to be the Devil) can appear in the night and turn you gay.
Take a Third Option: A character with sufficiently high stats may have a choice during a random event that wouldn't be available otherwise. Usually these are ways out of events that would otherwise hit you with a penalty no matter what you choose.
Tangled Family Tree: Any dynasty that doesn't ruthlessly purge its heirs can start looking like this, as the sons and daughters start their own families that link with other families, creating webs of family connections. And that's just for Christians; Muslims add polygamy into the mix, pagans can take concubines whose children may be heirs to titles from anywhere at all, and Zoroastrians can not only take concubines, but there's that whole incest thing to mix everything up.
The Theocracy: Any holding administrated by a bishop or other religious figure counts on the small scale, though they're often vassals to another, higher-ranked secular ruler. Popes, caliphs, ecumenical patriarchs, and religious leaders of the reformed pagan faiths are the more obvious high-ranking ones, and are often (but not always) independent.
Thicker Than Water: Rulers who are members of the same dynasty are automatically allies, and they will frequently come to one another's aid when circumstances allow. Of course, this won't always stop them from trying to kill one another when one stands a chance of inheriting the other's titles, but then no family can be perfect.
Treacherous Advisor: If someone both holds a court position under you and doesn't like you very much, that's an almost-guaranteed recipe for trouble, as they'll be much more willing to join Plots against you and have quite a bit of Plot Power. If one of them is your Spymaster, you're basically just hanging a "Please Kill Me Quickly" sign around your neck.
Turbulent Priest: See The Missionary; this is what those characters become of you're one of the pagan rulers in question and you decide you're not going to tolerate them spreading their venomous lies. Within your own realm, Priests can be generally Turbulent in much the same way your secular vassals are.
Unreliable Narrator: Especially in the case of traits like "Possessed", which might just as well describe an entirely mundane character trait or condition in modern times.
If you don't quickly marry off your children or others in your court, they can marry people on their own initiative. These do not come with alliances, and the woman in question may be a dribbling retard or a raving lunatic with many undesirable traits.
Uriah Gambit: A perfectly valid (if unreliable) way of getting rid of uppity vassals, possible claimants to your titles and love rivals is to send them in battles where they may be wounded, slain or taken as prisoners. If they get captured by the enemy side, you can refuse to pay the ransom for their release, since they are unable to plan against you while imprisoned. There are no diplomatic penalties for doing these things, except the prestige malus you get if you actually lose battles in the attempt.
Vestigial Empire: Say goodbye to the Empire of Byzantium note and welcome the Byzantine Empire of Russia! (Unless it stops being vestigial.)
To a lesser extent, the Holy Roman EmpireKingdom of Germany as well.
Tends to be averted (for both Byzantium and the Holy Roman Empire) in the sequel. A large part of this in the case of the HRE is the abolition of the Realm Duress mechanic (which used to result in the Kingdom of Germany routinely suffering complete implosion in the 1080s).
More generally, you don't lose a title until it's taken by a rival claimant, usurped by whoever already holds most of its de jure lands, or you lose all of your lands. Even if the Byzantine Empire is reduced to Constantinople and surrounded by hostile Turks, so long as no one else has enough Byzantine land to declare itself Basileus, then Byzantium will remain an empire.
Video Game Caring Potential: Much, much more difficult than the alternative. Rebellious vassals mean that you are forced either to tyrannically crush dissidents or face part of your realm breaking away, and opportunistic states are a constant danger, meaning keeping the peace while maintaining order is on its own difficult. However, it is there. Keeping low taxes on your peasants and burghers, stubbornly sticking through thick and thin to popular law, gifting your vassals the money they need to develop their lands, (and even giving money to nobles outside your kingdom if you have provided all that your developing kingdom needs) caring and nurturing your offspring and ensuring they are provided for, and even vassalising a state which has been attacked by a larger one and paying for its preservation via tribute to the attacker... it's possible to be nice. It's just not easy.
Video Game Cruelty Potential: Pretty intensive. You start playing and then after a few hours of gameplay you realize you've been spending most of your time and effort assassinating six-year-olds so that your literally-idiot nephew can inherit the throne of Bavaria.
Among other things. This game is essentially to 4X games what Dwarf Fortress is to city management sims, both in complexity and cruelty potential.
It is absolutely amazing how much murder, imprisonment, and disinheriting one can find themselves doing in the sequel when trying to get a female successor.
The Legacy Of Rome expansion allows Byzantine nobles to have their opponents blinded and castrated in order to remove them from the succession.
Video Game Historical Revisionism: Inevitable, and as usual for Paradox the extent to which it applies is a topic of debate. One major deviation, however, falls under Acceptable Breaks from Reality since it would be something of a Game Breaker. When a Mongol Great Khan died, all other Mongol military activity was to cease and the leaders were obliged to return with their armies to Mongolia to see the "election" of the successor. Historically, this was the only thing saving Western Europe from annihilation when Ogedei Khan died in 1241. This rule does not apply to the Mongols in either Crusader Kings.
In particular, the fact that some of Yemen's rulers in earlier start dates are completely fictional has attracted controversy.
We Are Struggling Together: Vassals can band together in an alliance against their liege for various petty reasons. However, vassals will do this even if they are being invaded by a larger outside threat, such as the Mongols.
In Crusader Kings II, vassals can now found factions, demanding stuff like independence, lower Crown Authority, Elective Succession or something similar. It is not uncommon for a large realm to have a dozen different factions, which, however, only have one or two members each and thus do not revolt yet.
We Have Reserves: The AI for some reason thinks its funny to send soldiers that just spent a month marching and retreating back into battle, no matter how many times they have already been smacked down.
It does this because there is always a chance that if you are besieging a province, an attacking army will manage to interrupt the siege and set it right back to square one. If you're defending or have beaten off an invading AI opponent they will hang back and let mounting debt and attrition, the first of which they don't suffer from, weaken the player instead.
The Mongols in the sequel both subvert this trope and force the player to use it: Mongols do not suffer attrition, but can't reinforce their units. Therefore, the only way to beat them is to basically send every soldier you have against them until there aren't any Mongols left.
Won the War, Lost the Peace: Out of the four eras covered by Paradox (this game, Europa Universalis, Victoria: An Empire Under the Sun and Hearts of Iron) the first game is the easiest game for conquering the entire map; with a decent start (England, say) you can do it in two generations. It is also the game where revolutions are the most dangerous; you can easily lose the entire thing as vassals rebel against you in vast quantities during a Succession Crisis or realm duress event. Even if you have claimed the entire map, holding it and trying to build a stable, united super-kingdom is a game in and of itself. Equally, in the second game you can easily win a war, ignoring some small civil disturbance down south, and then march back home to deal with it only to gaze in horror as that tiny rebellion has flourished into a multi-duke plot against your throne, and your exhausted army has no means of dealing with it...
Crusader Kings I
Asskicking Equals Authority: Some inheritance rules (based on either Salic or Semi-Salic Consanguinity) favour the son with the highest martial score rather then the eldest (Primogeniture). This was taken out in the second game.
Artificial Stupidity: The game has no clue how to deal with the movement paths of armies, which make for some interesting detours.
The Computer Is a Cheating Bastard: Computer factions never go into debt, so they're able to keep their armies fully mobilised at all times, and are always able to pay the transport fee over bodies of water, leading to interesting things like the Sultanate of Oslo and the Emirate of Wessex.
Cosmetically Different Sides: Played straight here. Even when Muslims were made playable with the Deus Vult expansion, there wasn't really much difference between them and the Christians, mechanically speaking.
Disability Superpower: While carrying hefty martial and lesser stewardship and health penalties, blind characters get a bonus to their diplomacy and intrigue.
In Spite of a Nail: There aren't many fixed historical events, but those that are tend to happen no matter what else occurs. For instance, The Teutonic Knights will be eventually formed even if the Crusades fail and the Baltic is already converted.
You ALL Look Familiar: Played straight in the first game, in that there are only so many individual portraits for each culture.
Crusader Kings II
Abduction Is Love: Subverted. Certain pagans will abduct female courtiers when they sack settlements, and the rulers have the option of taking them on as concubines — even if they're already married to someone else. However, this carries hefty opinion penalty, ensuring she will hate her abductor. It's possible for the "Fell in Love" event to happen between a ruler and their stolen concubine, but the event is bugged, and treats that concubine as an illegitimate mistress in related sub-events.
The second game lets players choose the name of his/her character's newborn children, so one can either avoid this trope or intentionally cause it.
In addition, there is a random chance for the child to be named for a parent or grandparent from both sides of the family. This means that if you give a character a silly name, chances are it will spread.
Some cultures follow a given name plus fathers name with adjective for their full name (with their dynasty name being left out but considered a part of their longer name). Combined this with the parental name sharing aspect mentioned before and this can result in such things as Bob Johnson with a son named John Bobson or even Bob Bobson.
Alien Space Bats: The 'Sunset Invasion' DLC for Crusader Kings 2 involves the Aztecs invading Europe in the 13th century. Yes, really. Although reaction has been mixed since it goes well beyond the usual alternative history of the games, from a gameplay standpoint, it balances out the fact that Western Europe rarely has to worry about the arrival of the various Hordes in the east which can decimate eastern nations.
Artifact Title: Zig-zagged. The DLCs for the second game allow you to play as a heathen or a plutocrat, and even the original game allowed you to play as a non-royal noble, a non-Crusading Orthodox ruler, or a woman. However, there's plenty of kings going on crusades throughout most of the game, even if you're not one of them. Furthermore, non-Catholic religions get their own means of waging holy war on unbelievers. Finally, said heathens and plutocrats are only available to the player if they decided to spring for the DLC; those who choose only to play the base game only have access to Christian feudal lords, as was the case in the original game.
Artificial Stupidity: The AI has no clue how to deal with the Decadence system for Muslim rulers in Crusader Kings II. As such, most of the larger Muslim dynasties have a nasty tendency to implode if left in the hands of the AI for too long.
Asskicking Equals Authority: Differs from the first game significantly; in the sequel, the "Invasion" casus belli works like this. Essentially, you petition the Pope/Ecumenical Patriarch/Caliph/other relevant religious authority to sanction an ass-kicking to steal someone else's title. It can be used without a claim, but only if you're smaller than the target.
The Adventurer system and Peasant Rebellions also allows for unlanded title claimants to amass their personal army to invade you for land.
And Pagan rulers from The Old Gods DLC can invade any single province that borders their lands and claim it without giving a hoot for any of this "legal basis" business. The Norse can do this to any non-Pagan coastal province.
Authority in Name Only: The sequel introduces the concept of "Crown Authority" which measures how much power a king holds over the nobility - A king with little or no crown authority can't even revoke vassal titles or prevent nobles from waging independent wars.
Authority Equals Asskicking: The Crown Authority mechanic encapsulates this trope. The higher it is, the better a ruler is able to keep his vassals in line, preventing them from launching independent wars, attacking one another (overtly), or passing their titles to another ruler's vassal by inheritance when they die.
Barbarian Hero: The Old Gods introduces adventurers, who can be both significant threats and potential allies.
Belligerent Sexual Tension: Crusader Kings II has an event chain that starts with a neighbour complaining, potentially followed by you sending roses, potentially followed by romance.
The Berserker: If your character is a Viking, he can become one in battle and gain a trait for it. This gives his martial skill a substantial boost.
Big Fancy House: Patricians in The Republic get a family palace that is treated as a completely separate holding from those that are on the map. Like any other holding, it can be upgraded to provide bonuses to income, levies, and other areas.
Black Vikings: The strictest interpretation is technicallypossible as of The Old Gods. Even in the base game, though, it's possible for a character to inherit his name, culture, and religion from his native-born father but his looks from his exotic-born mother. Displaced courtiers will also try to find a court that's most similar to their own culture and religion, which is usually fairly nearby but can end up being quite far afield indeed. For instance, Abyssinian Miaphysites ending up in Greece or Asia Minor after the Fatimids steamroll their corner of the world.
There's an event chain which begins with a neighbour boring you and sending envoys asking for money, and you can nail the envoy's hat on his head or send roses to him. If you nail the hat, you become an impaler and makes everyone around mad at you, with an option at the end of the chain saying something along the lines of "Perhaps I should begin planting roses?"
In one of the Improve Intrigue event chains, you can frame a nobody for jewellery theft. Thirty years of in-game time later, your ruler will suddenly wake up in the night and realize the man is still in the dungeons for a crime he didn't commit, and will rush to the dungeons to let him out after a nightmare, while your character takes a hit to their piety.
Chaotic Stupid: The Arbitrary trait is described as a character that cares little for right and wrong, and choosing things almost at random (it is represented by a six sided die). It also comes with a decent drop in vassal's opinions and stewardship. A lunatic, on the other hand, will do extremely random things (such as assigning their horse to a the council) and your vassals will LOATH you for it.
Colour-Coded For Your Convenience: Crusader Kings II uses different hues of the same colour to indicate similarity in its various map modes. On the political map mode, the Iberian Christian kingdoms for example share similar shades of yellow and red, while their Muslim neighbors are green. Similarly in De Jure Duchies mode, all English, French and German duchies are coloured in different shades of red, blue and white, respectively. The Kingdom of Burgundy is ... well, guess.
For the Religion map mode, Shi'a and Sunni Muslim are represented by similar but distinct shades of green, while Orthodox Christianity is purple and Catholicism is in white. Heresies have differing shades from their mother religions.(Fractelli is light brown, while Cathar is light blue). Realms with different religions from their liege have strips across them.
The Computer Is a Cheating Bastard: The Mongols have giant armies that completely ignore supply limits, thus allowing them to concentrate in unbeatable numbers, while the player cannot counter this due to still being limited by supplies.
The Conqueror: Any character who presses an Invasion claim can receive this nickname if he wins (and he'll deserve it, since winning an invasion involves conquering an entire kingdom in one go). They may also be a Young Conqueror, depending on their age.
The Old Gods, which adds new mechanics for the now playable pagan nations, including raiding;
Sons Of Abraham , adding new features to all of the Abrahamic religions and adding Judaism to the mix.
Crystal Dragon Jesus: Sufficiently strong pagan rulers can, under the right circumstances, reform their respective faiths, creating an organized religion with a formal priestly hierarchy and written holy texts. It's implied that these reforms are inspired by contact with and directly patterned after the Christian and Islamic religious bodies.
Defensive Feint Trap: In the sequel, this is the Altaic cultures' signature tactic, "Retreat and Ambush." It's widely considered one of the most powerful tactics in the game.
Defiled Forever: A subtle example — married courtiers are not exempt from pagan concubinage, and being taken as a concubine cancels the marriage automatically.
Dark Horse Victory: There's an achievement for conquering England as Svend II of Denmark, a somewhat more obscure monarch who also had a claim on the throne, rather than William of Normandy or Harald of Norway.
Death of the Old Gods: Unreformed pagans are more easily converted by Abrahamic missionaries, have a harder time of winning converts of their own from those religions, and are very prone to splintering amongst themselves. If no single leader arises to reform a given pagan faith into an organized religion, it's quite likely that that faith will wither away under the pressure of holy wars and missionaries.
Delivery Stork: Used as a short-hand to indicate that a particular character is pregnant.
Since the historical archives go back so far, The Prophet Muhammad is listed in the database. If you look at his character sheet, however, his portrait is blocked out, the only portrait in the game to have this property.
If you only read the drop down when using the Liege Creator DLC, you would think that being openly (well, as openly as medieval times allow for) homosexual is purely a penalty to the diplomacy stat. Well, it does more than just that. Most people will dislike you for being homosexual... except other homosexuals who will like you better. This opinion bonus also stacks with attractive...
The ''Game Of Thrones'' mod itself is an increasingly detailed model of Westeros, including "unlucky" modifiers for ruling Harenhall (but only if Harrenhall was conquered with dragons) and negating the "Kinslayer" penalty if Stannis or Renly kill Cersei's children.
Disability Superpower: Averted so very hard in the sequel; where negative congenital character traits, such as being inbred or having dwarfism, generally lack a positive bonus. The same goes for negative Health traits, which will affect either your fertility (ability to make heirs) or stats.
"Bonus" cosmetic additions that add extra portraits, historical dynasty flags, unit sprites and music...
... And mini-expansions like Sword of Islam and Legacy of Rome which make Muslim rulers playable and add new gameplay mechanics for Orthodox rulers, respectively. Paradox kept its promise to add new features to the basic game so players won't be forced to buy the expansions, but this hasn't stopped some fansfrom accusing Paradox of money-grubbing.
Dueling Scar: In the sequel, it's possible to receive one in battle or a duel. It's shown on the character portrait and adds a small monthly prestige bonus.
Easter Egg: Paradox Development Studio's main staff are in-game as landless Swedish courtiers.
Exotic Extended Marriage: Muslims can have a maximum of four wives. Pagans and Zoroastrians get one wife and the option of multiple concubines, all of whose children are considered legitimate.
Expansion Pack World: The patch that comes with Rajas of India will extend the game map well to the East, including the entire Indian subcontinent and more of Siberia and the Central Asian steppes. Earlier expansions already extended the map southward into Africa, though on a much smaller scale.
Eye Scream: Legacy of Rome gives Byzantine emperors the option of putting out the eyes of captured pretenders.
This feature also gets extended to all leaders with Greek culture.
419 Scam: You can be contacted by someone claiming to represent an Abyssinian prince. If you have the "Scholar" trait, you can reply by pointing out that the names in the message aren't Abyssinian.
Gambit Pileup: Crusader Kings II introduced the ability for characters to form secret conspiracies to achieve some goal or another, called "Plots." It's pretty much inevitable that at least two are going to crash into each other sooner or later.
Game-Breaking Bug: A King-Bishop is allowed to become the predicted next Cardinal, but is not allowed to become a Cardinal. Thus, if a King-Bishop becomes the predicted next cardinal (which is a distinct possibility due to the "secular power" modifier) he will prevent others from becoming Cardinals while himself never becoming a Cardinal, inevitably reducing the College to a tiny number.
Game-Favored Gender: CKII allows a male-biased inheritance law that allows women to inherit if no males are available for all non-Muslim cultures (agnatic-cognatic), and full female inheritance rights for the Basque culture and Cathar heresy (such as absolute primogeniture). Even then, though, female rulers and/or heirs result in opinion penalties, which doesn't affect male rulers and/or heirs.
Paradox did add female-preference inheritance in a later patch, but only for modders (by default, no realm starts with it and there's no way to switch to it). What is not moddable is that the default marriage is patrilineal (the children is of the father's dynasty), with a marriage being matrilineal having to be specifically chosen (and the AI prefers not to accept such marriage offers unless it directly benefits them).
Groin Attack: As of Legacy of Rome, castration is an option for Byzantine emperors to inflict on their captured foes.
Hello, Insert Name Here: You can name all your children in Crusader Kings II. Since the AI often names children after their parents or grandparents, it is entirely possible to accidentally introduce a branch of the family who all name their children "Poo PantsMcTwat".
Hereditary Republic: While all Republics in The Republic DLC are elective, if you're good (and rich) enough, your family can just keep winning election after election with sufficient funding.
Hell Gate: One chain of events in the sequel has an actual Gate to Hell open as a result of an earthquake, complete with wailing and gnashing of teeth. Fortunately, it's not too hard to close.
Hopeless War: This is what Harold Godwinson's defence of England is set up to look like during the conquest. He faces not only the larger army of William the Conqueror, but also Harald "Hardruler" of Norway. Luckily, Harold has some very loyal vassals and a superb-rated spymaster.
In Crusader Kings II, the sanest way to keep the throne as Harold Godwinson is to assassinate William the Bastard, since his claim on the English throne dies with him.
Horny Vikings: The Old Gods lets you take control of a selection of Norse warlords during the height of the Viking invasions of Western Europe.
Hot Consort: Your spouse can have the "attractive" trait. The actual appearance of the character can sometimes subvert this—they might appear to be very beautiful or handsome, but various traits they possess will make them repulsive to everyone.
Istanbul Not Constantinople: Patch 1.09 for the sequel introduces this system, with certain provinces and titles being renamed depending on the culture of their ruler. "Suomi" will become "Finland" under Swedish rule, for example.
Individual cities and domains can also be renamed by the player who owns them, who can then invoke this trope, as well as Egopolis.
Jeanne d'Archétype: An event chain in Sons of Abraham can put one in your court. They even get a special exemption to the prohibition of women being marshals and leading troops.
Kingmaker Scenario: Rival claimants to a contested throne don't always have their own landed titles, so they'll often depend on the backing of a powerful noble within the realm to lead Factions to enforce their claims. These nobles frequently end up being Kingmakers both figuratively and literally, at least when their faction wins.
King on His Deathbed: Rulers who are rendered Incapable get a regent appointed on their behalf, with all the court intrigues and power plays that that implies. They also usually don't last very long.
The Maiden Name Debate: In very rare cases, characters can arrange matrilineal marriages, whereby the groom and any children the union may produce are adopted into the bride's dynasty instead of belonging to his own.
Merchant Prince: ...and allows players to become one of these within the great merchant cities of (among others) Italy and the Hanseatic League.
Messianic Archetype: If you reforge the Persian Empire as a Zoroastrian ruler in "The Old Gods", you can declare yourself Saoshyant, the Messiah foretold by Zoroaster himself, who will put the world to order before it ends. This will give you a huge relations bonus with Zoroastrian vassals, and a smaller one to your descendants (similar to how Muhammad's descendants get a bonus with Muslims). Actual messianic character may vary.
Noble Fugitive: You can invite claimants to other titles to your court. If they accept, you then have the option of fighting on their behalf, whether their claim is rightful or otherwise. Succeed, and you've won an ally for life.
Alternately, they could serve in your court as one of your advisors, and you can marry them to your sons or daughters (matrilineally) have have their children in your dynasty inherit their claims.
Obligatory Swearing: A probably unintended example happens if you're playing a Finnish pagan. Since all references to divine figures in event flavour texts are replaced by pagan gods, one event has the possible response: "Thank Perkele [my child] isn't shy." Perkele was an alternate name for high god Ukko in pagan Finland, but in modern Finnish it's a swear word, equivalent to the English "fuck". The response becomes very humorous with this added context.
Passed Over Inheritance: The second and third in line for a title get strong claims on that title when the heir inherits. Even if they aren't particularly ambitious themselves, other nobles may start factions on their behalf to put them on the throne, even without their express consent.
Patronymic: A feature introduced in the sequel - characters from certain cultures (Scottish, Norse, etc.) gain their father's name after their own.
Permanent Elected Official: Doges under the new mechanics for Republics are elected for life, not any set term like in modern representative republics.
Press X to Die: Depressed characters can commit suicide from the Intrigue menu. This can actually be useful if your current character is iffy but your heir is good. You can also perform any number of tyrannical acts before offing yourself, allowing your heir, who remains blameless, to reap the benefits without the (very severe) penalties that normally follow.
The Promised Land: As of Sons of Abraham, it's possible for Jewish kingdoms to return to and restore the Kingdom of Israel.
Protective Charm: In Sons of Abraham, you can buy a holy relic, which gives a major boost to your piety, can be paraded around to help pacify the peasants, and gets passed down to all future rulers. Of course, whether it actually is a relic depends on how cynical you are.
Rape, Pillage, and Burn: Pagan rulers can launch raids against religious enemies for Plunder without explicitly declaring war first. This can net them an awful lot of gold in one go, as well as a female captive or two who can later be forced to become your ruler's concubine and bear him heirs.
Earlier, Legacy of Rome introduced a Factions mechanic, allowing vassals to unite against their liege over some common grievance. When the faction finally makes its bid for power, the leader of the faction also leads the rebellion.
Robin Hood: A secret event chain in the sequel deals with this famous brigand and you have a chance of playing the legend straight or trying to subvert it.
Regent for Life: The sequel introduces regencies for underage rulers, and sometimes regents won't give up on their power so easily.
Regime Change: In the sequel, you can press the claims of anyone in your court against any other title. If it's a lower-tier title and you win the claim war, the new holder usually becomes your vassal; if it's the same level as yours or higher and independent / under the same liege, it translates to an automatic alliance.
Royal Harem: Muslim rulers get multiple marriages, while Zoroastrians and pagans get concubines to go along with their one legal wife. All children from a Muslim father are considered legitimate, unlike those produced by mistresses in Christian nations. Children of concubines are equivalent to legitimized bastards.
Self-Imposed Challenge: Any of the hardest starts in the game (Generally considered to be, in order: Satrap Vandad of the Karen Satrapy in the Old Gods start, Isaac, Duke of Khazars, a Jewish vassal to the Tengri Cumanians, and the Khan of Khazaria in the Old Gods start, who is also Jewish, but even harder to play as due to a lack of a liege to protect him).
Sex Slave: Pagan and Zoroastrian rulers can take captive women as concubines and breed heirs upon them.
Shown Their Work: The amount of research put into history and genealogy in the sequel is incredible. One can find lists of Byzantine, Russian or German rulers dating back centuries to Constantine, Rurik and Charlemagne, including character traits and family relations. Even minor Irish counts can trace their family line all the way back to the fourth century, and the Papacy goes back to the third Pope, Anacletus, in AD 79!
Sword of Islam expands on this, giving Muslim characters the ability to observe Ramadan and go on pilgrimages to Mecca. Its main feature, the dynastic decadence system, is based on medieval Muslim historiography, especially as described in the Muqaddimah.
Start My Own: As of Sons of Abraham, if a Fraticelli ruler captures Rome, they can install their own Fraticelli Pope as a religious head totally separate from the Catholic Pope. Likewise with Iconoclasts who hold Constantinople, for an Iconoclast Patriarch.
Thrown Down a Well: In the second game, you can throw prisoners into an oubliette if you want them to hurry up and die but can't or won't execute them yourself for whatever reason.
Title Drop: In the second game, there's a possible random event during the summer fair intrigue event where a wandering band of minstrels are playing in your fair. Your options to respond include requesting that they perform the play "The Crusader Kings".