Video Game / Etrian Odyssey IV: Legends of the Titan

Soaring to the next destination!

Etrian Odyssey IV: Legends of the Titan is the fourth installment in the Etrian Odyssey series, being the first entry for the Nintendo 3DS, and was released in 2012 in Japan and 2013 everywhere else.

The game's story begins in the city of Tharsis, which is located in the midst of a beautiful, sprawling savannah known as the Windy Plains. Governed by a noble court, the city has been in the brink of becoming a Ghost Town due to a lack of interesting attractions for tourists and explorers. The only interesting spot for them is the impressive view of an Yggdrasil... but, unlike the ones grown next to Etria, High Lagaard and Armoroad respectively, this one is placed very far from Tharsis; and because of the many dangers that await in the open field plus the costs and difficulty that ensue due to the travel, no one has been able to get there... yet. Ten years ago, a skyship crashlanded close to the city, and the local Wharf Master studied it to learn the required technology to build more like it, thus reigniting the hopes to travel more easily to the mythical World Tree. With this hope igniting, your guild, once registered, is encouraged to undertake an epic trip to reach Yggdrasil, so this news can entice other explorers to visit the city and improve its economy.

The game marks a major departure from previous installments in the series. While the Dungeon Crawling gameplay, RPG mechanics and series-specific features remain intact, the game expands upon the then-situational overworld exploration first seen in the third game to offer a full-fledged open field, which is divided in four major areas. They can be explored while the party is driving a Global Airship, and over the course of the game said vehicle can receive attributes to improve travel. In the overworld, it's possible to find FOE like in the dungeons, as well as natural hazards that have to be worked around (such as cyclones, wind currents and dense snowstorms). Not all is bad, however: The party can also find food that can be either consumed to earn buffs or effects that prove benefitial for dungeon navigation; and from time to time, they can find friendly characters who travel in their own skyships, either looking for items or needing help during battle. Certain sidequests will ask the player to locate something in the overworld and mark it on the map so the exact spot can be reported accordingly to complete the task at hand.

Also, due to the distant placement of the Yggdrasil (and being indeed the final destination rather than the setting of the adventure), the strata found in the game take place in the overworld. These strata, known here as Mazes, hold the key to open the way to the Yggdrasil. Some of these Mazes are revealed to feature other civilizations, though whether they're friendly or hostile has yet to be found out. Other locations in the overworld include the Caves, which are miniature strata that share the themes and some aspects of the Mazes, but on a reduced scale; not all Caves are required to complete the game, as some are tied to sidequests and special activities. Both Mazes and Caves have their own layouts and designs, and thus it's possible to draw maps to avoid getting lost.

Lastly, befitting the system it was developed for, the game makes use of the StreetPass functionality so players can share their Guild Cards with each other. This also allows a player to locate certain optional treasures hidden in the overworld. And by registering certain QR codes (available online), it's possible to unlock special sidequests and complete them to obtain rewards.

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This game provides examples of:

• Abandoned Laboratory: The Hall of Darkness, accessible during the postgame, used to serve as the grounds where a safeguard to the Calamity was being developed. The Imperials working on it had to resort to sealing it, as it ended up killing many employees.
• Acquired Poison Immunity: Played with, unlike in the previous games. Normally, the game employs a mechanic where inflicting a status ailment or bind on an enemy or ally will increase that character's resistance to that effect for the remainder of the battle. But one of the unlockable classes, the Arcanists, have a skill called "Release Spell" that undoes this, thus resetting the chance rate to inflict the ailments and binds to enemies; it also works against bosses.
• All the Worlds Are a Stage: Two examples appear in the end- and postgame respectively:
  • The Forgotten Capital plays with the trope, as most of it is locked behind an ancient gate with four locks, and to open it the player's party has to detour to a multi-colored portal that takes them to a route that goes across previously uncharted parts of the game's cleared dungeons, each of which includes a lectern that can be activated to open one of the locks in the final dungeon. Activating all four wll open the Capital's entrance gate, allowing the characters to explore it. The connected dungeons are revisited in reverse order: Echoing Library (fourth), Golden Lair (third), Misty Ravine (second), Lush Woodlands (first); and in each of them the original setpieces and gimmicks will return, now applied to harder puzzles than before.
  • The Hall of Darkness, which serves as the postgame's Bonus Dungeon, mixes gimmicks seen in several previous dungeons. The first floor is a large, intrincate maze that uses the Wrap Around corridors of Misty Ravine (also seen briefly in Forgotten Capital); the second floor used brand-new setpieces (green damage tiles and a dark invisible maze that can only be mapped efficiently by studying the rooms with the aforementioned damage tiles); and the final floor mixes the previous elements with the miasma hall from Miasma Forest (a Mini-Dungeon), the ice walls and a mechanism to melt them like in Underground lake (another mini-dungeon), and a complex metapuzzle to weaken the True Final Boss (analogous to the puzzle to weaken the boss of Golden Lair). The entire dungeon also employs a darker, gorier palette of Echoing Library.
• Always Accurate Attack: The Sniper's Snipe attacks always connect, even against enemies with sky-high evasion, and inflict one of three types of binds. Leg binds, in particular, ensure that all attacks used on the inflicted are effectively Always Accurate Attacks - useful in the series in general, but especially in this game thanks to said high-evasion enemies.
• Angels Pose: The cover of the game has the Medic, Landsknecht, and Fortress (all female) in the forefront striking such a pose.
• Arbitrary Headcount Limit: In each of the major dungeons you can encounter an NPC who will increase your party to six (there are six slots to place five characters, the NPC will take up the sixth slot). However, the NPC will only join for that dungeon, and the last floor of that dungeon. And once you beat the boss of that dungeon, the character joins your party permanently, and you're back to only five characters.
• Artificial Animal People: The Sentinels are humanoid animals that were created by humans as part of the Yggdrasil Project to help restore Earth after a world-ending calamity.
• Autobots, Rock Out!: The Battle Theme Music for minibosses, "The End of Raging Winds", eschews the chiptune-flavored music for boss battles the series was used to (including the original version of that same track in the third game) in favor of a mix between rock and electronica. It helps that the soundfont is more varied and advanced than that for the games released for original Nintendo DS.
• Barrier Change Boss: The Cradle Guardian is capable of changing the hue of its protective plate over the course of the battle to shift its current elemental and melee strengths and weaknesses, cycling in the following sequence: Melee —-> Fire —-> Ice —-> Volt —-> Melee again. The hue indicates what it's currently most resistant against, and also hints at the current weakness. Fire plate is weak against ice, the Ice plate is weak against volt, the Volt plate is weak against fire, and the colorless plate makes it resistant against physical attacks and neutral against elements.
• Bears Are Bad News: In the first Land, there are bear-beast FOEs and bosses that will destroy a party with on-par levels if they don't prepare accordingly. Several of these bears are part of dungeon puzzles in which the player has to lure them towards wooden barricades covered with honey so that they can destroy those barricades and allow the player to progress.
• Beast Man: The Sentinels, a Servant Race that were presumably genetically engineered from regular animals. Fittingly, their playable class, Bushi, is The Berserker.
• Benevolent Boss: Most town leaders in the series are decent people, but the Outlands Count in this game is an even better boss, as he knows full well of the responsibilities of his office, frequently issuing orders intended to improve Tharsis and remove potential hazards for adventurers, acting as a capable diplomat with the Vessels and Sentinels, and making a decent effort to stand The Empire's demands. Sure, he's a pampered aristocrat with his fluffy lapdog, but when the chips are down, he considers his own life to be expendable if it will help protect Tharsis.
• BFS: The final class, Imperials, wield drive blades, massive swords with powerful Magitek motors built into the blade. They're so huge that they prevent the wielder from holding a second weapon, though fortunately regular sword skills can also be used with them.
• Big Boo's Haunt: The Hall of Darkness is a large facility stained with blood in its floors and walls, areas that warp explorers back to a starting point unless they pay attention to the toxic tiles' placement, wrap-around corridors like those of the second stratum (Misty Ravine), a room with a very stinky smell (like in the Miasma Forest mini-dungeon), and is home to an extremely dangerous monster. The last floor mixes the setting with Slippy-Slidey Ice World.
• Blackout Basement: A few areas on the second and third floors of the Hall of Darkness feature pitch black rooms with teleporter traps on the floor. In actuality, the safe places to walk coincide with the patches of poison on the floor in the adjacent rooms.
• Bleak Level: The fifth stratum in the game, the Forgotten Capital, is located in the renmants of the Yggdrasil after its demise, and hinted to be one of the extinct major cities of modern Earth. It has only one floor, but it makes up for it by featuring an unsettling atmosphere and a cramped layout, making it stand out from the relatively cheery previous dungeons (which, additionally, have to be revisited in order to start exploring this place). Interestingly, it doesn't have a boss (the opponent at the end, the Cursed Prince, is a Mini-Boss), but completing it leads to the reveal of the Final Boss, the Heavenbringer (the personified form of the Yggdrasil), who awaits in the Cloudy Stronghold. The Bonus Dungeon (Hall of Darkness) is even scarier, but at least it's to be expected due to it being an Abandoned Laboratory, so the impact factor isn't as big.
• Bonus Dungeon: The Hall of Darkness is an Abandoned Laboratory where Imperials used to work on a living failsafe should the Yggdrasil reach terminal corruption, only for that failsafe to end up killing everybody within and turn the whole place into a ghost building where all walls are stained in blood. In addition to hosting exceptionally strong enemies, it also has Wrap Around corridors, toxic puddles, a huge warp maze, ice walls and ice floors that can be melted and later restored (which has to be done from time to time for a successful navigation), a room with a strong stench of miasma, and in the end the aforementioned failsafe: The Insatiable Pupa (which can grow to become the Warped Savior).
• Boss-Altering Consequence:
  • The Boiling Lizard, which serves as the boss of the Golden Lair, has an abnormally high amount of HP. While it's possible to defeat it as-is, there's a way to weaken it before initiating the fight: As soon as your character party enters the room, the boss will begin chasing them; while the party dodges it, they can approach the scales that keep the Boss Room hot and use Ice Stakes to destroy them. Once the largest scale is destroyed, the whole room cools down and the HP of the boss is halved, thus giving the party a greater chance to win the battle.
  • The True Final Boss, the Insatiable Pupa, is not only exceptionally powerful but also very durable. If the party characters approach it as soon as they reach the last floor of the Bonus Dungeon, their chances of winning are very low unless they come fully prepared with maximum level, stats and gear. The easier method is to grab a nearby canister and then explore the last floor in its entirety to collect a set of chemicals in a specific order (which can be figured out by collecting a series of posthumous scientific papers which provide specific hints about the chemicals' order of application) and then apply the mix into the Boss Room before entering. While this doesn't show an immediate effect on the Insatiable Pupa during its larval phase, it does on its Warped Savior form, as it'll have its HP halved and unable to cast its ultimate attack (Ragnarok).
• Boxing Kangaroo: The game features a FOE called a Bounding Beast. It's a massive (its joey is taller than the average human!) black-and-white kangaroo monster that, naturally, fights using devastating punches and uppercuts. Later in the game, Palette Swaps of it appear as regular enemies.
• Bragging Rights Reward: Like in the third game, this gets exaggerated due to the quirks of the forging system. The ultimate weapon has 8 empty forge slots for maximum customizability, but for each slot you need to use an item you sold to the shop - which happens to be the unique drop of the True Final Boss. Hence, you'll need to kill that boss 9 times in order to fully empower that weapon. It gets more tedious this time, however, as there is a total of eight different types of Infinity +1 Sword that behave like that, forcing the player to slay the boss at least 72 times to get the perfect gear for their party.
• Breaking Old Trends: Unlike the last three games, which are all set around a single Mega Dungeon, this game instead features multiple dungeons spread across an overworld map.
• Brutal Bonus Level: The Hall of Darkness. Mixes up many of the gimmicks from previous dungeons, adds some new and is filled with Puzzle Random Encounters, that features powerful foes with different weaknesses to exploit but that are always found in groups specifically designed to fill in their flaws. For example, Red Lion is the strongest non-boss enemy in the game, but starts the battle sleeping...but he's usually found with a Hollow Magus, that can damage their allies and boost their power through the roof. So, just kill the Hollow Magus first, right? Wrong! Her evasion is insanely high, and sometimes she's found with a Thunder Spawn, which is one massive damage sponge and goes berserk if you kill one of its allies. Lastly, before facing the Super Boss you need to weaken it first by collecting a set of chemicals in a specific order that is only vaguely hinted through various lore entries scattered in the last floor. Have fun!
• Bubblegloop Swamp: There's a Mini-Dungeon example with the Noisy Marsh, located in the Scarlet Pillars. It's a waterlogged area inhabited by frog-like F.O.E. monsters that move diagonally (a very rare sight in the series).
• Carnivore Confusion: You can hunt at various points while flying to get food that gives you buffs. In the third area of the game, the food you get from hunting spots is rabbit meat. After completing the third area, you unlock the Bushi class, who are antropomorphic animals, including a rabbit as a possible choice. Or you can just recruit Kibagami the bull into your guild, then take him to the first area and make him eat the non-humanoid bulls there.
• Cast from Hit Points: The Bushi class of explorers can deal more damage to enemies and bosses by sacrificing some of their HP. Their moveset is risky overall, but with good planning they can deliver a ton of damage this way.
• Choice of Two Weapons: The game changes this up a bit. All characters can equip two weapons simultaneously upon unlocking Subclasses, though without the right skill, it's closer to this trope than Dual Wielding. Normally they'll still attack with only the "main" weapon, but switch to the "secondary" if they use a skill requiring that type of weapon.
• Contractual Boss Immunity: While the majority of bosses are immune to One-Hit Kill effects, the Fallen One only resists instant death, it's not fully immune to it, meaning a lucky instant death attack will end the fight instantly.
• Convection, Schmonvection: A notable aversion, considering the previous game played it straight with its volcanic third stratum. In Golden Lair, several of the Boiling Lizard's scales are scattered, which are hot enough to not only keep the whole area warm (including the water), but also inflict field damage to the player's character party upon proximity. The heat provided by the largest scales not only has a wider range, but can also prevent the party from approaching at all unless they do so from a specific direction.
• Cooldown Manipulation: Imperials are built around this trope. Their massive drive blades are capable of doing thousands of damage points to a single target, but the blade then overheats and they need to wait out several turns before they can unleash that attack again. In the meantime, several other skills help them reduce the turns spent overheated to increase their overall DPS.
• Cowardly Boss: Your party's first encounter with a Bloodbear starts out like this. You fight it until its HP are knocked down to about 50%, at which point it runs away from you to a lower floor where you have to go to finish it off.
• Critical Hit Class: The class proficiency of the Snipers allows them to score critical hits with their bow skills (normally, only regular attacks can crit) and increases critical damage. There are other classes in subsequent games that have similar features, usually in the form of passive skills that allow their skills to crit, but none are as focused on critical hits than the Snipers.
• Damsel in Distress: At one point, the Medium is abducted because she holds the key to awaken the true form of Yggdrasil, the Heavenbringer. The player's party goes through the fourth stratum (Echoing Library) to chase Prince Baldur, who is forcefully dragging her to the Yggdrasil. The party manages to defeat the Prince (who is then revealed to have been corrupted by the influence of Yggdrasil, and pulls a Heel–Face Turn), but it's too late: The Medium is now captive inside the Heavenbringer, but her determination to save the world allows her to force a restrain to the monster, allowing the party to defeat it in battle and rescue the girl.
• Disc-One Final Dungeon: The Echoing library, located in the homeland of the seemingly-antagonistic Empire (Cloudy Stronghold). The regal design, plus the ominous ambiance and the objective of rescuing the Medium from Prince Baldur, all portray this dungeon as the final destination for the player's guild. However, once the Prince is cornered, he takes the Medium with him through an emergency exit and the guild is distracted by the Cradle Guardian, the dungeon's actual boss. The real final dungeon is the Forgotten Capital, located beneath the withered Yggdrasil, but a long procedure involving the previous dungeons is required before it can be explored.
• Disconnected Side Area: Though previous games have featured large disconnected hidden paths back and forth through the floors, the Mazes in this game stand out in particular because they have large swaths of land you can't get to at first; you traverse them as part of the process of unlocking the final dungeon, and the enemies there are as strong as you'd expect endgame enemies to be.
• Drop-In Nemesis: In each mainland except Cloudy Stronghold, one of the Elemental Dragons will periodically start soaring around, and its motion and speed per step make them difficult to dodge. And if the party gets caught by it, the Elemental Dragon will shoot down their skyship, making them respawn in Tharsis with only 1 HP per character left and all food lost. Luckily, if the party manages to evade the monster, it will leave after a while and the mainland will be safe once again. The Great Dragon appears in Windy Plains, the Storm Emperor appears in Scarlet Pillars, and the Blizzard King appears in Snowy Mountains. During the Playable Epilogue, there will be sidequests that require performing tasks while the dragons soar, which further increases the difficulty (since the dragons will not leave the mainland this time); but once those sidequests are completed, the dragons can be finally challenged in Superboss battles.
• Dual Wielding: The Nightseeker class can use both hands to throw knives which, on top of causing damage, have a chance of inflicting ailments. In particular, Blade Flurry consists of an effective twofold strike, and causes even more damage if the enemy or boss is already suffering an ailment.
• Elemental Tiers: The game has this with the Runemaster class. Runemasters, unlike the Alchemist and Zodiac classes of previous games, have a drastic difference in what their three elemental spells do: volt spells target an entire line, fire spells deal splash damage, and ice spells pierce to hit the back line. The imbalance is heavily weighted to volt, as targeting a whole line for equal damage is better than targeting one thing for full damage and things next to it for splash, or one thing in each line, assuming there even is something in the back. Bosses which have multiple parts are a common thing as well, and volt spells hit each part for full damage, which is something neither of the two can do. While later tier spells just hit everything, that costs more TP, meaning volt is best for conserving it whether wandering around a labyrinth or fighting a boss.
• Enemy Scan: There is a Limit Break skill in the game that reveals the strengths, weaknesses of all enemies present.
• Escape Battle Technique: Starting from this game, the Escape option is present in the menu to try to escape a battle, though it's disabled in fixed encounters as well as boss and miniboss battles.
• Failsafe Failure: The Insatiable Pupa was originally created by the Imperials as a failsafe against the Yggdrasil should the latter get corrupted; to this end, the Pupa's objective was to absorb as much corrupted matter from the tree as necessary. Unfortunately, the Pupa itself got currupted as a result, and ended up killing nearly all scientists who worked on the laboratory (now known as the Hall of Darkness) where the monster was conceived. By the time the game's story concludes and the Playable Epilogue begins, the player's character party receives a key from the Outland Court (who in turn received it from a high-rank Imperial) which grants access to the Hall of Darkness, and once inside the characters have to find and slay the Insatiable Pupa.
• Fire, Ice, Lightning: In addition to bringing back the Landsknecht (which can perform follow-up attacks imbued with fire, ice or volt) and the now-classic Elemental Dragons, the game also brings in new characters and a new boss that invoke this trope:
  • The Runemaster class inherits the torch of the Alchemists and Zodiacs as the performers of fire, ice and volt AOE attacks (though unlike the previous equivalent classes, these operate differently in terms of the targeted enemies), in their case by way of casting magical Runes. However, they also have the power of casting Runes to increase the party's defense against one of the three elements, while at the same time reducing an enemy's resistance against it.
  • The Imperials have the Elemental Drives, which inflict a seriously strong damage to the targeted enemy. The skills in question are Flame Drive, Freeze Drive and Shock Drive. The catch is that the used Drive Blade requires a cooldown period before it can be used again (unless they use the special Ignition skill, which allows them to use the Drives for up three turns in a row, plus once again the turn after the skill expires).
  • The True Final Boss has three powerful attacks imbued respectively with the three basic elements, and they're powerful enough to potentially kill several characters or even the whole party. Learning how to evade or block these attacks will prove vital to survive and win.
• Flunky Boss: The second stratum boss, the Hollow Queen, summons other Hollow enemies during battle. As she does so, she places herself into the rear area of the battlefield, meaning that the attacks of the playable party's rear characters won't reach her until the summoned enemies are defeated.
• Frictionless Ice: Once you cool down the largest heating scale in a floor in Golden Lair, the whole area will cool down as well, freezing the previously warm water. This frozen water is completely frictionless, both for you and the F.O.E. present. This also applies to the ground ice in Underground Lake and Hall of Darkness (minus the need of cooling a scale; in fact, at one point you have to do the opposite by using the Black Flame to warm the areas in order to melt the obstructing ice walls).
• Glass Cannon:
  • The Bushi are capable of impressive damage output, but the associated skills are Cast from Hit Points. Given that they also can only wear medium-strength armor, they are prone to dying if not supplemented with healing.
  • Imperials can do damage in the thousands with their Drive skills, but doing so lowers their turn speed and imposes a defense penalty until the attack executes, putting them at risk of dying easily before they attack. Otherwise the class functions like a Mighty Glacier.
• Global Airship: By default, the game requires you to discover new locations (including the game's signature strata) by traveling manually across the overworld with the skyship. However, once the Geomagnetic Pole of a specifc region or stratum has been found for the first time, you can warp there instantly from the Hub City. And in the case of the strata, even if you return to one via a Geomagnetic Pole, the skyship will await you at the entrance as if you had once again reached there manually!
• Grail in the Garbage: In an early sidequest, you are tasked with recovering an armor set that was used as collateral in a bargain; the merchant only agreed because the armor was said to have been created by a minor master. When retrieved, it's unusable, and the merchant will angrily bestow it upon you, thinking he's been cheated. Unfortunately for him, a quick visit to the local blacksmith will reveal that the armor was indeed created by said master, and it's repairable for free!
• Guest-Star Party Member: During the main story of the game, you can optionally let a supporting character join you as you explore the last floor of the current stratum, until after the upcoming boss fight: Wufan in Misty Ravine, Kibegami in Golden Lair, and Logre in Echoing Library. Afterwards, you can choose whether or not to have them as permanent members of your party. During the postgame, Prince Baldur, Kirjonen and Wiglaf will join you when you confront for the first time the Great Dragon, Blizzard King and Storm Emperor respectively.
• Gusty Glade: The Windy Archive, located in Cloudy Stronghold, is a Mini-Dungeon version. It's a library where wind currents perpetually blow south, so the player's party characters have to know where to walk to properly navigate the place and avoid being blown back to the start. Strangely for a video game series that fully exploits the potential of every gimmick seen in each game's dungeons, these wind currents aren't seen anywhere else in the game (not even in the Bonus Dungeon, which otherwise brings back many familiar mechanics seen in previous locations), though their functionality was seen beforehand with the sea currents in the Undersea Grotto from Etrian Odyssey III: The Drowned City (and seen again in that dungeon in Etrian Odyssey Nexus).
• Herding Mission: There's a sidequest of this type taking place the Mini-Dungeon Golden Deer Keep. The player's character party is asked to lure a F.O.E., the eponymous Golden Deer, into a special jail installed by some guards from Tharsis at the entrance. The Golden Deer spends its time galloping around a pit bordered by small fences, but as soon as it sees the party it'll begin chasing them. The biggest caveat here is that the Deer is fast enough to gallop two tiles per turn while the party can only move one, so it's recommended to first explore the area in full to draw it in the map and devise a route to draw the monster's attention without getting caught. The reason is because, if the Deer catches the party, a battle will begin and the party will the need to attempt to flee from it, as defeating the monster will kill it and force the party to wait until it revives. Once the Deer is lured into the entrance where the jail is, it'll get trapped there and the mission will be a success.
• HP to 1: Getting caught by one of the Elemental Dragons or an Imperial airship while exploring the overworld will lead to the party's Global Airship being completely shot down, and the party's characters will reappear in Tharsis with only one HP each left (also, all they food they might have gathered will be lost).
• Impossibly Cool Weapon: Drive Blades, which are huge blades that are used by the Imperial class and motorized to inflict a massive amount of damage to the enemy in one swing. The only downside is that using them will lead to a necessary cooldown period to attack with the again, though upgrading certain skills will reduce that time.
• Increasingly Lethal Enemy: The game introduces Rare Breeds, glowing variants of normal Mooks and F.O.E.s that get stronger the longer you leave them alive. They also give your party much more experience points than normal, provided they don't run away first.
• Infinity +1 Sword: As per series tradition, the ultimate Superboss drop can be used to forge the strongest weapon. This time, though, there's eight of them, one for each weapon type, and they each come with eight empty forge slots. Purchasing and forging them uses up one copy of the boss's drop each time, so if you want to buy and optimize each of the ultimate weapons, you must defeat this boss 72 times.
• Interface Spoiler: The final floors of most of the dungeons have large swathes of untouched territory that can't be accessed. At the time. Before entering the final dungeon, the guild takes a secret pass through these unexplored areas to gain access.
• Invincible Minor Minion: The Imperial airships patrol the Cloudy Stronghold as if they were FOE, yet they cannot be fought in battle (much less defeated) and have to be avoided at all costs, because getting caught by one will fully incapacitate the Global Airship and make the characters respawn in Tharsis with only 1 HP each and all food that was gathered lost. By the time the characters earn the Empire's friendship (even being able to recruit Imperial-class explorers to the party), the airships are simply gone.
• King Mook: The game has the Berserker King (to the Bloodbears in Lush Woodlands), Hollow Queen (to the family of Hollow ghosts in Misty Ravine), and the Cradle Guardian (to the robotic sentries that patrol the Echoing Library). Some sidequest-related minibosses fit as well, such as the Baboon King (Angry Baboons and other related primates) and the Chameleon King (to the elusive Chameleons).
• Limit Break: The Burst skills, which operate differently from its equivalents seen in previous games. Instead of each character having their own gauge and/or individual skill to use, the Burst gauge is shared among all party members and, by filling it up during battle, can be leveled up from 1 to 5. As with the Limits in the third game, they're unlocked by finding their associated relics in the strata as well as by completing sidequests. Each Burst skill required the gauge to be at a certain level, and using it will consume the required load from the gauge (meaning that it'll have to refilled to use another skill if the resulting level isn't enough yet).
• Long Song, Short Scene: How long would you expect to spend in a single normal enemy battle in the first three strata? Even in this series, probably not 3 minutes and 20 seconds, which is how long it takes for the (first) normal battle theme, "Battlefield - Storm", to loop. In comparison, the battle themes heard later in the game are shorter.
• The Lost Woods: Lush Woodlands and Misty Ravine. By extension, this also applies to their respective overworld whereabouts, Windy Plains and Scarlet Pillars, plus the mini-dungeons located in them.
  • Lush Woodlands introduces F.O.E. so aggresive that, while chasing you, will break any cluster of fallen tree trunks obstructing certain corridors, which of course is a good thing; this concept is also seen in the Mini-Dungeon Dense Bushland, whereas the other mini-dungeons in the Windy Plains (Old Forest Mine, Small Orchard and Valley Spring) are more generic forest locations in comparison (the Old Forest Mine in particular doubles as a Noob Cave).
  • The Misty Ravine is a mystic forest filled with Wrap Around corridors, meaning that the map will display routes that end in a point but continue in another within the same axis; the remaining locations in the Scarlet Pillars rely on other gimmicks instead: Miasma Forest has a putrid smell in its central area's atmosphere that forces the player's characters to retreat after 10 steps, Moth's Garden have F.O.E. that won't aim at you unless you're engaged into an enemy encounter, and Noisy Marsh is a Bubblegloop Swamp with F.O.E. that move diagonally (a very rare sight in the series).
• Mana Burn: There's a sheep-like FOE in Scarlet Pillars that is capable of inflicting Sleep onto the party characters. If this happens, in the next turn the enemy will perform Dream Eater, which fully depletes their TP meter, rendering them unable to perform any special skills. This makes it a very dangerous opponent. This FOE returns in Etrian Odyssey Nexus (specifically in Western Shrine), and retains this ability.
• Marathon Boss: There are two bosses which, if approached directly and challenged at once, will be sporting a full HP bar which is often too large for the party's resources to handle. This will mandate walking around the floor or boss room to trigger certain map events that will weaken it to manageable levels, going from this trope to Puzzle Boss. The two bosses in question are Boiling Lizard (Golden Lair) and Warped Savior (Hall of Darkness).
• Mass Monster-Slaughter Sidequest: One late game quest in the game involve killing a bunch of foes in a particular dungeon. The problem is that only the monster that's currently being asked for counts - you can't get ahead by killing a bunch of a different monster for later. And if the monster in question isn't spawning via the Random Number God, you're in for a long slog, even if you can easily dispatch all of the monsters in question.
• Mecha-Mooks: The Echoing Library is guarded by two kinds of FOE: A dog-like automaton that lies inert and seemingly inanimate in certain spots, and an active humanoid robot that patrols the corridors. When the player's character party is seen by the latter, it will emit a loud siren from its klaxon to wake up the robotic dog so it begins to chase you. Dodging these enemies is vital for survival to make it to the end.
• Mechanical Monster: The Cradle Guardian is the King Mook of the robotic F.O.E. that roam the Echoing Library, and is capable of switching its strengths and weaknesses at will. It's summoned by Prince Baldur, who in that moment is being corrupted by the influence of Yggdrasil, and is kidnapping the Medium to revive the Yggdrasil.
• Metal Slime:
  • The game introduces the "Rare Breed" system, which gives all (non-boss) enemies a (very small) chance of appearing as this trope. Rare breed monsters are recognized by their shiny, golden color and give additional experience when they're killed. On each round that they remain in battle they give the message that their "glow intensifies" meaning you'll get even more bonus exp for killing them. Like all Metal Slimes there's a chance they'll run away each turn they're in combat, but you also can use ailments like leg binds to prevent their escape and keep them in the battle for longer. Rare Breeds also have an increased Action Initiative, letting them wreak havoc (or flee) before your party even gets to act. This system will see itself get reused for every subsequent 3DS entry in the franchise.
    
    F.O.E.s also have a small chance of spawning as a Rare Breed, and they can become incredible sources of experience once defeated. For overworld F.O.E.s, feeding them a rare version of their favorite food will also turn them into a Rare Breed. While Rare Breed F.O.E.s will never flee from battle, they get a stacking power boost each turn; with the innate speed bonus of the Rare Breed, they can easily cause a Total Party Kill if you don't pick your fights properly.
  • Across the overworld, you may see Pookas, who move incredibly quickly and can outrun you. Understandable, as they have only 1 HP and will go down at the first blow; when they die, they yield Books, which increase a single stat for one character, depending on the type of Pooka you killed. You'll have to outright guess and second guess if you want to teleport to the correct cave to ambush them.
• Metapuzzle: There's an optional metapuzzle in the Bonus Dungeon (Hall of Darkness) that doubles as a Boss-Altering Consequence, since solving it will give the player's character party a greater advantage when fighting the True Final Boss (whose room can be accessed with suspicious ease as soon as the party reaches the final floor). The huge maze that makes up for the last floor's layout has several navigation puzzles, which make use of assets and gimmicks based on previous dungeons as well as the earlier floors of the Hall of Darkness itself. As the characters work out their way through them, they find color-coded chemicals which are part of a powerful compound capable of weakening the Insatiable Pupa, but they must be inserted into a collectable canister in a very specific order. This order, in turn, can be figured out by gathering recorded hints that are also found in the last floor. The player is very likely to realize that the chemicals have been gathered in the wrong order; however, once they've fully explored the last floor and figured out the right combination order for the chemicals, they can discard the chemicals as initially gotten and re-navigate through the floor so the chemicals can be gathered again, only now in the correct order. With them stored in the canister, the party can head to the entrance to the boss's room to apply the chemical and prepare for the epic battle.
• Mini-Boss: There's the first Bloodbear found in Lush Woodlands, eventually-recruitable characters like Kibegami and Logre, Prince Baldur, and sidequest-related opponents like Baboon King and Sand Leviathan; all of them use the theme "Unrest — The End of Raging Winds" (a remixed version of the ocean battle theme in The Drowned City).
• Mini-Dungeon: The Caves are single-floored ecosystems with a relatively compact explorable area (usually a 3 x 3 map of quadrants worth 25 spaces each). And each of them has a specific purpose related to a request accepted in the Dancing Peacock in Tharsis, though a few of them are also linked to the main story. Completing a Cave awards a stamp and a brief description of the Cave and its inhabitants. The main dungeons are the much more complex Mazes, or Labyrinths, which are multi-floored locations with mini-bosses and a boss each. And every floor has its own large area (whose map dimensions are also bigger: 7 x 6 at most).
• Missing Secret: It's possible to save extra data from Legends of the Titan to the 3DS memory as a future-proofed Old Save Bonus measure. However, none of the other games in the series released for the system can read this data, leaving it as an odd remnant.
• Monster in the Ice: In both a Mini-Dungeon located in Snowy Mountains and the postgame Bonus Dungeon, there are FOE that are encased within large walls made of ice: Patrol Bat in the former, and Moth Lord in the latter. In both cases, it's possible at one point to melt the walls and thus bring back these creatures to life.
• Mook-Themed Level: Two mini-dungeons in the game are tailored for, and thus named after, the F.O.E. that inhabit them: The Moth's Garden in Scarlet Pillars (inhabited by Moth Lords) and The Golden Deer Keep (self-explanatory).
• Mystical White Hair: The Vessels usually have white hair. The only possible exceptions to this are potential Player Character choices: like all classes, Arcanists have Palette Swaps to pick from. However, all NPC Vessels have white hair.
• Nerf:
  • From this game onwards, each character can only equip one accessory at a time. This was in response to how resistance accessory stacking in The Drowned City outclassed wearing armor.
  • Skills learned from a subclass are now capped at half their usual max level.
  • Stat books return in this game, but their permanent stat increase caps at 10 per stat per character.
• Noob Cave: The Old Forest Mine, which is the first Mini-Dungeon visited in the game and a good place to learn the basics about the game.
• Noodle People: The Vessels are extremely thin, and just as frail as they appear. This contrasts them with the hardy Sentinels.
• Nothing Is Scarier: Cruel Slayers, which reside in Echoing Library, first appear as panther-like statues. You just know when you spot the first one that it's going to attack you, but you have to walk past it anyway. And it... does nothing. They don't activate until you're spotted by an entirely different FOE, at which point every Cruel Slayer in the area will wake up at once and chase you down at double speed.
• Obvious Rule Patch: The introduction of Formaldehydes in The Drowned City made it particularly easy for players to obtain difficult boss conditional drops early on, then save up/grind for the end-game or even ultimate equipment unlocked from them. To prevent this from being exploited anymore, all ultimate equipment in Legends of the Titan also requires materials exclusive to the post-game Bonus Dungeon in addition to boss conditional drops.
• Oddball in the Series: The game has a large number of deviations from the usual Etrian Odyssey formula:
  • It's the only game to have overworld exploration as part of the main story. Sure, Etrian Odyssey III: The Drowned City has seafaring, but it's not strictly required to complete the game.
  • Instead of a 30-floor dungeon divided into six strata, you instead have six "Mazes" spread across the lands. Furthermore, none of the Mazes in this game have more than 3 floors, when each stratum in other games is usually 5 floors high.
  • It's the only game not to have you traverse up or down Yggdrasil. Instead, Yggdrasil itself becomes the Final Boss.
  • It's the only game to have "Caves", one-floor mini-dungeons that each have less floor space than traditional labyrinth floors. This may be why this game's equivalent of strata are surprisingly short. Mini-dungeons return in Nexus, but they're called "Mazes" and are much wider on average.
  • It's the only game that doesn't have an FM synth version of its soundtrack. The DS games only have FM soundtracks, and the other 3DS games have them as optional alternate soundtracks.
  • Its "horrifying stuff is happening" theme, "Imminent Calamity", follows a distinctly different format from other themes of its line in the series, and for the longest time was not shared with any other track in the series (Etrian Odyssey I and II, as well as their respective Untold remakes, have "Red and Black"; Etrian Odyssey III and V have "Unknown Menace"). It was finally brought back in Nexus.
• Ominous Latin Chanting: Unlike the instrumental used in-game, the super arranged version of the Final Boss theme (also used by the True Final Boss in its second phase) features lyrics from Dies Irae.
• The Paladin: The Fortress class focuses on defending the other members of their guild by receiving enemy damage in their place, though they also have more offensive versatility than the Protector from previous games.
• Palette Swap: While reskinned enemies aren't a novelty in the series (and neither are Underground Monkeys), this game has a notable example with the Lion: While all of them are asleep by the first turn, the attack power of each new version is higher; and by the time you meet the Red Lion in the Bonus Dungeon, expect to deal with an attack so strong (Biting Flurry) that will likely instantly kill many or all of your party members if their defense isn't high enough.
• Plant Person: The Vessels, found in the Misty Ravine, are plant-based beings who are initially reclusive towards humans, though this does change for the better as the game progresses. In the Japanese version of the game, they share the same name as the first game's Forest Folk (Mystics), implying that they're the one and same (or at least related).
• Player Data Sharing: Starting from this game, the series allows exchanging cards via the StreetPass feature of the Nintendo 3DS, eliminating the need to go into a specific in-game mode to swap cards. Additionally, the player can choose one member of their guild to be shown on their card, showing off their stats, equipment, and skill build, and other players can recruit a copy of that character provided their guilds each have at least one guild member who has reached the featured character's level, though the registered character cannot level up or change equipment. If StreetPassing cards is not feasible, the player can convert their Guild Card into a QR code and scan other players' QR codes to get their Guild Cards.
• Proactive Boss: The three Elemental Dragons will periodically and respectively fly above the first three overworld areas (Great Dragon in Windy Plains, Storm Emperor in Scarlet Pillars, Blizzard King in Snowy Mountains), and over the course of the game they must be avoided at all costs until they fly away (being caught by one of them will cause it to sink your Global Airship and make you return to Tharsis with all your party's characters having only 1 HP each left). During the Playable Epilogue, when undertaking certain postgame sidequests, they'll fly above their areas of preference on a permanent basis, requiring you to complete said sidequests while avoiding them at all times. Only after completing those sidequests, you'll unlock others that task you to finally confront the Dragons in battle, one at a time.
• Production Foreshadowing: In a game that otherwise doesn't feature Legacy Boss Battle fights (outside of the staple elemental dragons), the surprise appearance of Iwaoropenelep as a postgame superboss serves as a tease for the Untold remake of the first game, which would be the next installment in the series.
• Pupating Peril: The True Final Boss of the game is the Insatiable Pupa, a horned teal insect shaped like a beetle which was created as a failsafe against the Yggdrasil should it go out of control. Unfortunately for the Imperials who were working on it, the Pupa proved to be too dangerous after it absorbed too much power from the Yggdrasil, to the point of being corrupt, so it was sealed. One of the last surviving members of the research team devised a chemical compound capable of weakening the Pupa, and after a series of failed combinations between the constituting substances it finally found a suitable formula to created, but the compound could not be obtained in time before the researcher's passing. When the player's party arrives the last floor of the Pupa's whereabouts, they can gather clues on the compound's formula so they can insert the chemicals (found within dispensers located in specific locations) in the correct order to a canister which they can also find in this floor. If they succeed, then the canister can insert the chemical into the room of the Pupa and greatly weaken it prior to the boss battle, giving the party an advantage. But even in this scenario, the Pupa will hatch onto its ultimate form, the Warped Savior, so it's still far from a cakewalk.
• Reasonable Authority Figure: Every authority figure is one, having nothing except the best interests at heart for their land and its residents, as well as its neighbors. However, Prince Baldur lost it in the face of the threat of his empire being completely destroyed, resorting to more extreme measures. After the party foils his plan and he is rescued by the Medium, even he settles back into this role, aiding you in fighting the Great Dragon when it threatens his people.
• Remilitarized Zone: At first, the fourth mainland (Cloudy Stronghold) is heavily patrolled by the aerial forces of the Empire. Being spotted by one of them will cause the party's skyship to be gunned down, resulting in the characters being brought back to Tharsis with critically low health and any food gathered lost. By the time you complete the fourth Stratum (Echoing Library) things change for the better, as you'll not only be able to wander around the Stronghold freely but also hire Imperial-class characters for your party. The Echoing Library itself remains an example of this trope, however: Those robotic F.O.E. will continue patrolling the rooms like they own the place (which is why the stratum revolves around sneaking through the corridors without being spotted, though in one instance you have to make them chase you as they're obstructing the path to the boss room).
• Schizo Tech: The Empire has plenty of powerful, warlike skyships whose engineering far surpasses that of Cilan's (and by extension Tharsis') primitive skyship tech; Wynne (from the Berund Atelier) even expressed surprise at this, since she used to think Cilan was the sole expert in flight vehicles (the irony is that Tharsis' skyship tech is derived from the Empire's, because Logre shared his knowledge on the subject during the ten years he spent under the Whirlwind persona outside the Empire). The Echoing Library (the first major dungeon accessed in the Empire's homeland, Cloudy Stronghold) is patrolled by mechanized statues that, upon detecting intruding explorers, use klaxons to awaken robotic dogs in order to corner the intruders. The Bonus Dungeon, Hall of Darkness, shows that many Imperials have also investigated in the field of biochemistry, as they created the Insatiable Pupa as a failsafe should the Yggdrasil rebel against humanity, though their knowledge is shown to be insufficient as they're unable to properly keep control of this very creature. The rest of the Cloudy Stronghold proper has a very ancient design reminiscent of pre-Columbian civilizations, and the remaining societies (humans from Tharsis, Vessels and Sentinels) rely on rural costumes and lifestyles.
• Servant Race: Three such races exist in the game. They're the Vessels, the Sentinels and the Hollows. As recorded in the Hall of Darkness, they were created by humans to assist in the completion of the Yggdrasil Project, and dubbed "servitor races".
• Slippy-Slidey Ice World: The Sacred Mountains are a very cold tundra in the overworld where the falling snow not only makes sight more difficult but in some areas, it also prevents the Skyship from ascending higher. It is home to various Caves (including the Underground Lake, which is ice-themed too — it is a maze made of ice walls but can be turned into a maze of warm water moats with the Black Flame) as well as the third stratum, Golden Lair. Lastly, the last floor of the Hall of Darkness has several ice walls that make up for a maze in a section; turning on a certain device will melt them, but also the frozen tiles scattered through the floor (which means they become pits and thus are impassable).
• Spooky Silent Library: The sixth maze of the game, the Hall of Darkness, is a sinister, dark, long-abandoned library slash research facility where the shelves and walls are caked with blood. And for full effect, unlike every other track in the game, the level's background 'music' is a rather creepy ambient piece.
• Status Effect-Powered Ability: The Nightseeker and Sniper both specialize in Status Infliction Attacks and exploiting them:
  • The Nightseeker's class proficiency gives them a massive damage boost when attacking an enemy suffering from a status ailment, while their Assassinate skill has a higher chance of successfully causing a One-Hit Kill on such an enemy.
  • The Sniper, meanwhile, learns Snipe Mastery, which gives them a higher chance to critically hit an enemy that is bound (which synergizes well with their class proficiency, which increases the damage bonus from a critical).
• Stone Wall: The job of the Fortress class is to redirect, to themselves, the attacks aimed at their comrades. As a result, they not only have a high defense but also a staggering amount of HP. It's not uncommon to reach the cap of 999 HP with one such character even before they hit level 99. As a downside, their attack power isn't very high.
• Superboss: After the quests involving the Elemental Dragons (including the respective ones where you defeat them) are completed, you receive a quest from a mysterious person who tells you that the Dragons' defeats broke a seal keeping a very powerful black dragon captive. That dragon is known as the Fallen One, and it's now free. You can find it in a hollow northeast of Cloudy Stronghold, and it's extremely powerful. Interestingly, it is not immune to being defeated via One-Hit Kill, though the chance rate is only 1%.
• Suspiciously Similar Substitute: Boiling Lizard is nearly identical to Salamander from Heroes of Lagaard and its Untold remake. Both are fire-type bosses that, prior to fight, have to be properly approached (which requires careful planning). They also have aids during the battle (Salamander summons its babies, Boiling Lizard expels red-hot scales), and can also attack violently with their tails. Interestingly, both of them appear in Nexus, and in the same dungeon at that (Golden Lair, originally from Boiling Lizard's home game).
• Tech Tree: Though the series has always had the system of "some skills require leveling up other skills to learn them", but it wasn't until this game that the skill list started being displayed as a flowchart of skills rather than a one-column list to better show this trope.
• Toggling Setpiece Puzzle:
  • The game features a Mini-Dungeon (Underground Lake) that consists of a large maze made of ice walls, and some of the walkable tiles have Frictionless Ice. At first, nothing can be done in this area, but when the character party acquires the Black Flame from another mini-dungeon, they can light a large chalice at the center to warm up the whole area. When this happens, all ice walls will thaw and become walkable tiles... but the previous slippery tiles will thaw as well and become impassable moats; as a result, the maze will change its configuration and layout, and the FOE that used to be frozen will warm up and come back to life. Extinguishing the flame from the chalice will return the maze to the previous form. The party has to work around both shapes of the maze in order to fully explore it and complete the sidequests that involve it (finding a piece of primeval ice and finding the fossils of a long-deceased monster).
  • Much later in the game, you'll reach the Hall of Darkness, whose last floor features large ice walls and slippery (but passable) ground tiles. The principle is the same: Turning a furnace on with the Black Flame will warm up the whole floor, thawing the ice walls to open paths but melting the ice floors to make them impassable; the party has to figure out the right navigation procedure with these perks in order to find the color-coded chemicals and put them into their canister in the proper order so they can weaken the True Final Boss before facing it in battle.
• Uncommon Time: Library of Puppets, the stratum theme in Echoing Library, uses 7/8 signature time.
• Underground Level:
  • Golden Lair is a rocky labyrinth located within the cold Sacred Mountains, serving as the third stratum. In each floor, there are red hot scales expelled from the Boiling Lizard (the boss), but they can be excised with Ice Stakes. However, also in each floor, there's a larger-than-usual stake whose removal will restore the whole floor to its original low temperature, freezing the water in the process and allowing the player's characters to slide through them. It is home to the Sentinels, who ask you to get rid of the Boiling Lizard and find a cure to an ancient illness; they eventually lend their services to Tharsis (which leads to the availability of the Bushi class of combatants).
  • The Mini-Dungeon locations in the Sacred Mountains are Underground Levels, but each of them has its own gimmick: The Cramped Nest is a small maze with sharp, spiky walls, only some of which can be traversed (trying to get through the others will cause pain to the characters, reducing their HP). The Toxic Cave has F.O.E. that vomit harmful poison to the floor (this is actually good if the poison falls over gathering spots, as it's the only way to obtain a kind of material that is unobtainable otherwise). Lastly, the Underground Lake is a Slippy-Slidey Ice World maze made of ice walls that can be melted once the central spot's chalice is lit with the Empire's Black Flame, and restored when the chalice is turned off again (since the area's temperature also determines whether the ice floors are slippery but passable or warm yet impassable, this effectively gives the whole maze two toggleable layouts, and swapping between them is necessary to fully explore it).
• Unintentionally Unwinnable: One of the quest chains in the final world map involves a quest where the airship is flown over certain symbols. In the event that the quest is accidentally canceled after activating all of the symbols, this cannot be repeated and the player is forced to either begin a new game or use NG+.
• Useless Useful Spell: After the first three games having skills and combos to make TP sustainability a breeze, subsequent games from IV onward nerfed the potency of TP replenishment skills, making them a mixture of too expensive, too weak, and/or too situational to warrant the skill point investment.
• The Very Definitely Final Dungeon: The Forgotten Capital, revealed once the Yggdrasil Tree withers and dies. It can only be properly explored after opening the Kings' Gate, for which the player's party has to look for the credentials of the Four Kings while venturing into the secret parts of the previous main dungeons.
• Vibroweapon: Drive Blades are large mechanical engine-powered swords wielded by the Imperial class. When an elemental Drive attack is called for use, the Blade unleashes it with tremendous power, but then releases some steam and heats, requiring a cooldown period (namely a number of in-battle turns) to be used again (there are certain skills that shorten the period, though).
• Video Game 3D Leap: A presentation upgrade. The previous games all showcased 3D dungeons and world maps, but the fourth game upgrades the battle interface to 3D backgrounds and enemies, which have been carried over to the series (even applied to the first two games' remakes) since.
• Well-Intentioned Extremist: Prince Baldur of the Yggdrasil Empire. By all accounts, he was a Reasonable Authority Figure when he first took the throne. Faced with the slow withering of his subjects' land, however, he's resolved to awaken the eponymous Titan in order to reverse it, even knowing that doing so would doom the Vessels and Sentinels to a slow and excruciating death by the Titan's Curse. Thus, it's up to the player's guild to stop him.
• Wrap Around: There are passageways in the floors of the Misty Ravine which, due to the influence of the effect of the atmosphere's miasma, end at one point in the map and resume in an opposite end; the terminals can be either horizontal or vertical. It is here where the number icons of your map's legend come very handy, as otherwise it's pretty easy to get disoriented during navigation. The Bonus Dungeon takes this to the logical extreme - the wrap-arounds in the first and third floors are all located in the map's borders.

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