History ThatOneBoss / FinalFantasyXIV

* [[spoiler:Hydaelyn]], the last trial bosbefore the FinalBoss of ''Endwalker''. The boss uses massive [=AOEs=] that hit like a truck with the gas pedal floored. The boss starts with attacks that are signaled with red, green, or blue images; red means get close, green means get far away, and blue means stand diagonal. Mess up any one of them, and you'll be lucky to survive, since you've only got about 1.5 seconds to move to the right spot. There's also a double-tankbuster, which needs both tanks to get close to each other; one tank trying to brace the hit isn't enough, since it's going to be a OneHitKill even with mitigations fired off. Halfway through, the boss will start summoning waves that sweep the field, which are slow-moving projectiles that can hit multiple times. The waves even apply a stack of Vulnerability Up every time they deal damage, and multiple waves are summoned at once, requiring you to do a very delicate dance to avoid them all. And when the boss gets low on health, multiple waves and stacking mechanics will start being applied at the same time. This will leave the entire party running for dear life, and give the healers barely any time to fire off their spells for the damage that can't be avoided just to keep everyone alive, since even one mistake is almost a guaranteed death.

* The third fight against Ran'jit [[AndNowForSomeoneCompletelyDifferent has you playing as Thancred, defending Minfilia from Ran'jit]]. This is difficult not just because Ran'jit is a DamageSpongeBoss, but because there's a lot of mechanics that [[MarathonBoss make the whole fight feel like a drag]]. Thancred doesn't deal much damage as a Gunbreaker, forces you to rely on a recharging potion to recover HP, and occasionally needs to go invisible to avoid being detected by Ran'jit. The whole time, Ran'jit will still be spamming large AOE attacks that cover a lot of the arena, meaning you'll need to dodge for a few seconds and position yourself before using the Duty Action to end the effect and deal a sizable chunk of damage. If you get hit during this, the attack is interrupted, and you've got to try it all over again. In addition to Ran'jit hitting like a truck, the sheer amount of HP he has means that even a few mistakes can cost you towards the end of the fight, and it really feels like it should end ten minutes before it actually does. [[spoiler:Plus, once it's over, Thancred gets what appears to be a ReallyDeadMontage, left bleeding and with no aether remaining. But no, he gets an UnexplainedRecovery by the time you catch up to him, making it all feel like a colossal waste of time that doesn't add to the narrative.]] It's not uncommon to hear people switching to "Very Easy" mode for this Duty not just because it's hard, but because they want it to be over with.

* [[spoiler:Hydaelyn]], the last trial before the FinalBoss of ''Endwalker''. The boss uses LightEmUp attacks everywhere, and all of them are massive [=AOEs=] that hit like a truck with the gas pedal floored. The boss starts with attacks that are signaled with red, green, or blue images; red means get close, green means get far away, and blue means stand diagonal. Mess up any one of them, and you'll be lucky to survive. There's also a double-tankbuster, which needs both tanks to get close to each other; one tank trying to brace the hit isn't enough, since it's going to be a OneHitKill. Halfway through, the boss will start summoning floods of light, which are slow-moving projectiles that sweep across the field and can hit multiple times. The waves even apply a stack of Vulnerability Up every time they deal damage, and multiple waves are summoned at once, requiring you to do a very delicate dance to avoid them all. And when the boss gets low on health, multiple waves and stacking mechanics will start being applied at the same time. This will leave the entire party running for dear life, and give the healers barely any time to fire off their spells for the damage that can't be avoided just to keep everyone alive, since even one mistake is almost a guaranteed death.

* Avoid listing examples caused by Unrestricted Party settings, as the very nature of that option can cause strange boss behaviors when sequence broken. (e.g. breaking Ifrit's Infernal Nails too fast).

* Susano, the level 63 trial, has mechanics that involve good movement and/or positioning to make it easier for other players to handle. For example, one of the mechanics involves marking a player, pushing them back, and forming a line of safety through the marked player and the boss. If the marked player was at an unfortunate position at the time, this can cause the mechanic to damage the rest of the party. This is also when failing mechanics starts applying vulnerability stacks, meaning failing mechanics constantly makes it harder to survive.
* For many players who skipped Alexander, Lakshmi can be a WakeUpCallBoss since this is the first time you have ever ''had'' to use the ATB-mechanic. It's not uncommon for players to have moved it to a different part of the interface and accidentally miss it when they pick up Viril, or even know ''when'' to use the Viril since Lakshmi's only hint (Past her "Group hug" attack) is moving to the centre of the stage.
* 4.1 has a rematch against the primal [[spoiler:Lakshmi, as she suddenly appears right in the center of the Ala Mhigo alliance's meeting room]], this time as a solo duty. The primal will constantly spawn orbs of aether that advance towards the [=NPCs=] that are behind you. If even one Echo-less NPC gets touched by the aether, they become [[BrainwashedAndCrazy tempered by the primal]], and the quest fails. The aether clusters grow in number as the battle goes on. Although you have an NPC (and later a second NPC) helping you destroy them, your ability to attack the aether is on a short cooldown. This can be disastrous if you don't time it right or don't hit the aether when they're bunched up. With the Echo on Very Easy mode, the aether-attacking ability covers the entire arena, which makes the battle much easier. But if you don't want to take the help, it's fighting a primal along with an EscortMission, and it's a huge headache.

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%% When listing examples, try to list them in chronological in their respective folder. Normal Raids and Alliance Raids have their own bullet points exempt from this guideline.

* The meta context during time of release. Boss fights won't have the same experience when overgeared or played in later expansions. Avoid listing examples from unsynced fights, as the very nature of that option is liable to cause AI-breaking sequence breaks. (e.g. breaking Ifrit's Infernal Nails too fast).
* Extreme, Savage, and Ultimate are considered {{Bonus Boss}}es, as they're technically optional encounters. Unreal trials are essentially remastered Extreme Trials and are identical in battle design, scaled up to match patch content.

* 4.1 has a rematch against the primal [[spoiler: Lakshmi]], who will constantly spawn orbs of aether that are advancing towards the [=NPCs=] that are behind you. If one person gets touched by the aether, they become [[BrainwashedAndCrazy tempered by the primal]] and the quest fails. The aether clusters grow in number as the battle goes on and although you have an NPC (and later a second NPC) helping you destroy them, his and your ability to attack the aether are on a short cooldown and can be disastrous if you don't time it right or don't hit the aether when they're bunched up. Unlike other main story quests that give you an Echo buff if you fail and try again, the Echo will ''not'' help you in dealing with the aether clusters.[[note]]However, with the Echo on Very Easy, it ''will'' let the aether attacking ability cover the '''entire arena''', so while the aether clusters will not decrease in number, you won't have to chase them down and can simply spam the action to take care of them.[[/note]]

** Speaking of Alexander Prime, the last boss of the Alexander raid series is notable for having strong auto-attacks, a cleave tank buster that can almost one-shot the raid if not careful, and the fact it requires a Tank LB3 to survive its ultimate attack at a specific moment to not die. The second phase of the fight involves Alexander pulling off a TimeStandsStill while it teleports away somewhere and does the wide laser beam attack. As the fight progresses, its previous mechanics start stacking up with this one. Lastly there's a phase where four of its minions portal out of the arena and four members of the party must go after them. Preferably the DPS should go, but if any one of the minions survives, the party wipes.

** The Demon Tome is similar to the Demon Wall in Amdapor Keep, with a few added skills. It doesn't advance and you can't be knocked off the edges, but instead will occasionally cast Disclosure and begin to glow. This signals that you need to run along the sides of the arena to the backside of the Tome. Anyone on the wrong side of the Tome when it closes will be killed instantly. And the same skill that causes Slow and Heavy gets used, meaning your chances of getting to the other side if you get hit with Heavy are slim to none. If that wasn't bad enough, the Demon Tome will cast Words of Winter after a while, which will cover the ground in ice and make you slip and slide in the direction you attempt to go. And then it will cast Disclosure again, meaning you've now got to jet to the other side of the Tome while dealing with ice physics. Even players who know what's coming can still struggle here if they get hit with Heavy or can't move themselves just right.
** The Everliving Bibliotaph is the dungeon boss, and he's a doozy. At three intervals throughout the fight (roughly 85%, 55%, and 25% HP), Bibliotaph will begin casting Void Call. Platforms on the ground will light up, and they will need a certain number of players to stand on them in order to cancel their summon. One light on the platform means one player needs to stand on it to cancel the summon, two lights mean two players, and three lights mean three players. If you don't coordinate how to deal with this beforehand, you might not get to the lights in time, which means summoning powerful adds that can really ruin your day. Plus, Bibliotaph will mark players with targets that will set down a purple void spark which will remain in place for a duration, periodically pulsing to inflict a stack of vulnerability on those in the area. If this spark ends up next to some of the lights you need to stand on, you can pretty much kiss that one goodbye and hope you can deal with the add.

* The third fight against Ran'jit [[AndNowForSomeoneCompletelyDifferent has you playing as Thancred, defending Minfilia from Ran'jit]]. This is difficult not just because Ran'jit is a DamageSpongeBoss, but because there's a lot of mechanics that make the whole fight feel like a drag. Thancred doesn't deal much damage as a Gunbreaker, forces you to rely on a recharging potion to recover HP, and occasionally needs to go invisible to avoid being detected by Ran'jit. The whole time, Ran'jit will still be spamming large AOE attacks that cover a lot of the arena, meaning you'll need to dodge for a few seconds and position yourself before using the Duty Action to end the effect and deal a sizable chunk of damage. If you get hit during this, the attack is interrupted, and you've got to try it all over again. In addition to Ran'jit hitting like a truck, the sheer amount of HP he has means that even a few mistakes can cost you towards the end of the fight, and it really feels like it should end five minutes before it actually does. [[spoiler:Plus, once it's over, Thancred gets what appears to be a ReallyDeadMontage, left bleeding and with no aether remaining. But no, he gets an UnexplainedRecovery by the time you catch up to him, making it all feel like a colossal waste of time that doesn't add to the narrative.]] It's not uncommon to hear people switching to "Very Easy" mode for this Duty not just because it's hard, but because they just want it to be over with.

*** The second boss fight, or a fight with boss'''es''', 724P-operated Superior Flight Unit (A-lpha), 767P-operated Superior Flight Unit (B-eta), and 772P-operated Superior Flight Unit (C-hi), and each alliance is responsible for one. There's several mechanics that can be spilled into the area where the other parties are at, and a number of the AOE markers are hard to properly avoid as a result of the enclosed area each Alliance has. Infamously, a line stack-up mechanic where the boss shoots out a laser. If this is aimed at another party, expect that party to have several fatalities due to taking two (or more) lasers. Not helping is that it an attack where all three will summon a sword, and attack everything on that side, meaning you need to figure out where all three blades are aiming to avoid being hit.

** The Tower at Paradigm's Breach is the final of three parts, and it's appropriately difficult. However, the Red Girl is tough even by that standard. Besides shooting out the same red orbs as other bosses in the raid, she also requires you to learn about white and black coloring; black destroys white, and white destroys black. This is important, as Warriors of Light need to destroy certain color blocks to escape otherwise-inescapable OneHitKill attacks by attuning to the right color and smashing the blocks. Halfway through, the Red Girl also turns you into tiny polygonal ships, making the fight into an UnexpectedShmupLevel where you have to navigate the ship and destroy a core before the fight can keep going. Finally, there's zones around the arena that instantly kill you the moment you touch them. And the Red Girl may become a PuppetMaster to force you to move in a direction towards these kill floors, while you can do nothing but watch it happen. It's not a question of if you'll die, but how many times you'll die. Finally, several players who played the raid shortly after release reported experiencing seizure-like symptoms from this fight, including motion sickness, nausea, headaches, dizziness, and vomiting. While Square Enix quickly issued a patch to correct the problem, the fact is that this fight might ''physically hurt you to play it''.

* The Puppet's Bunker has two in particular.
** The second boss fight, or a fight with boss'''es''', 724P-operated Superior Flight Unit (A-lpha), 767P-operated Superior Flight Unit (B-eta), and 772P-operated Superior Flight Unit (C-hi), and each alliance is responsible for one. There's several mechanics that can be spilled into the area where the other parties are at, and a number of the AOE markers are hard to properly avoid as a result of the enclosed area each Alliance has. Infamously, a line stack-up mechanic where the boss shoots out a laser. If this is aimed at another party, expect that party to have several fatalities due to taking two (or more) lasers. Not helping is that it an attack where all three will summon a sword, and attack everything on that side, meaning you need to figure out where all three blades are aiming to avoid being hit.
** The third boss fight, 905P-operated Heavy Artillery Unit. It also has "aimable" lasers, one is a conal that targets several DPS players, the other marks two tanks with a tank busting beam. Another mechanic has it mark three players, jumping on them with an small AOE, with the last person targeted becoming the safe zone as the boss immediately does a donut-style AOE attack after. So while the targeted players have to get away from the alliance, they can't stray too far because the safe zone will be out of reach. Then there's the cavalcade of arena-based mechanics that require spatial awareness, ranging from bullets, Pods that strike the arena based on the program that is uploaded, and circles that require a certain amount of players to soak damage, or they risk hurting the entire alliance.

* The Mist dragon, the last boss of the 4.4 dungeon The Burn, can be pretty tough for a dungeon boss. It has several room wide attacks that are difficult to dodge, either because they are ones players end up placing themselves, or cover just about the entire arena. All of them are difficult to dodge due to the small arena, and will freeze you if caught in it, requiring another player to break you out of while also placing Vulnerability on you. It also makes ice circles on the ground which stick around for a while that usually target the tank, which limits the space you can move, and can create AOE markers that, for the first time, go out in a specific direction based off a pulsing arrow, making it hard to tell initially just where you can go to avoid it. It has two unique phases to it also; a DPS check where you must kill three dragon heads that slowly fill the arena with an AOE that, if not quickly dealt with, will hit everyone, and a phase where it goes invisible and covers the area with mist, forcing you to find where the dive attack AOE is coming from to avoid being hit. All of these are things a Trial boss would have in difficulty, and it wipes a large number of parties simply because of how mechanically intense the fight is for a MSQ boss.

* Coming right before Titan in terms of dungeons and trials is the last boss of [[ThatOneLevel Brayflox's Longstop]], Aiatar. In addition to using poison debuffs liberally throughout the fight, she also spams a poisonous AoE pool that will quickly overtake the battleground. Leaving the boss on the pools will have her HP regenerate, meaning the tank can't dawdle and has to pull the boss out of the puddles, or risk a long battle. [[AntiFrustrationFeatures Toxic Vomit was changed in 6.1]] to instead have her create a triangle of poison blobs that Burst in an AoE attack. As the fight proceeds, she'll spit two ''asynchronous'' triangles each time.
* After fighting your way through the Longstop, Titan awaits, and he's a notorious WakeUpCallBoss. The major problem is his arena is over a fatal fall and many of his attacks involve pushing you off the edge, well outside of the range of any resurrection spells. The arena also shrinks significantly throughout the fight. Hard Mode, at least in its early lifespan, is particularly notorious for Landslide's [=AoE=] flat out lying due to the dodgy hit detection and latency. Two blue lines signify where the ''animation'' will trigger, but not the attack itself. Many a players are subsequently punted off the arena despite seemingly have dodged.

** Diabolos, the last boss of Dun Scaith. The boss which immediately precedes him would have probably been on this list as well, however, once Diabolos enters his second phase, Diabolos Hollow, he begins to copy her attack pattern only ramped UpToEleven. To make things worse, for the first part of the battle, Diabolos Hollow has complete damage immunity and guaranteed critical hits. If that wasn't bad enough early in the patch's life people didn't realize the immunity functioned like Stoneskin and required them attack until it broke. The fight is also one of the longest fights in the game that isn't a Savage or Ultimate, having two full phases filled with several dangerous mechanics.

* Also in 4.4 is a solo duty where you have to fight Sadu. She uses some VillainousValor to keep getting back up after beating her, each time having slightly more HP than the last. Most of this isn't that bad, but her last phase automatically puts a strict one-minute time limit on the fight before an instant kill meteor impacts. The problem is this phase also has her spamming all the AOE gimmicks she has been using throughout the fight at once, leading to a frantic situation where the player has to not only avoid the stacking [=AOEs=] but do enough damage to her in time. Even if she does CastFromHitPoints to revive her adds, there is barely any time to even rely on that. Immediately after the fight with Sady, [[AndNowForSomeoneCompletelyDifferent you have to play as Y'shtola in a fight against Magnai]] where you also have to make sure Hien stays alive. While this part is thankfully more merciful, wiping out at any point means starting at Sadu all over again.

* Also in 4.4 is a solo duty where you have to fight Sadu. At first the battle isn't that bad but then you get to her last phase which automatically puts a strict 60 second time limit on the fight before an instant kill meteor impacts. The problem is this phase also has her spamming all the AOE gimmicks she has been using throughout the fight at once, leading to a frantic situation where the player has to not only avoid the stacking AOEs but do enough damage to her in time. Even if she does CastFromHitPoints to revive her adds, there is barely any time to even rely on that. And not only this but immediately after the fight you have to play as Y'shtola in a fight against Magnai where you also have to make sure Hien stays alive. While this part is thankfully more merciful if you manage to wipe at it you have to begin the duty from the fight with Sadu again.

* Coming right before Titan in terms of dungeons and trials is the last boss of [[ThatOneLevel Brayflox's Longstop]], Aiatar. In addition to using poison debuffs liberally throughout the fight, it also spams a poisons AOE pool that will quickly overtake the battleground. Leaving the boss on the pools will have its HP regenerate, meaning the tank can't dawdle and has to pull the boss out of the puddles, or risk a long battle.

** The above gets even worse when trying to get the dragon's Blue Magic spell, Cold Fog. Not only does it require dealing with the boss as [[GlassCannon the glassiest of glass cannons]] in the form of the Blue Mage, which must survive in order to learn the spell, it also requires the party to ''deliberately fail the DPS check'', leaving the whole party frozen for ten seconds with a debuff and letting the dragon go absolutely ham on them. It's not at all uncommon to either have an unsynced party run the thing (multiple times if necessary), running a mixed BLU/tank/healer party to carry the Blue Mages, or a combination of the two. It says a lot that many players save this spell until after the Masked Carnivale.

** The second boss fight, or a fight with bosse'''s''', 724P-operated Superior Flight Unit (A-lpha), 767P-operated Superior Flight Unit (B-eta), and 772P-operated Superior Flight Unit (C-hi), and each alliance is responsible for one. There's several mechanics that can be spilled into the area where the other parties are at, and a number of the AOE markers are hard to properly avoid as a result of the enclosed area each Alliance has. Infamously, a line stack-up mechanic where the boss shoots out a laser. If this is aimed at another party, expect that party to have several fatalities due to taking two (or more) lasers. Not helping is that it an attack where all three will summon a sword, and attack everything on that side, meaning you need to figure out where all three blades are aiming to avoid being hit.

* Many of the level 50 trials in general have become this - simply due to overexposure. The 7th astral era arc is very ''very'' long, and unlike other "Post-game" scenarios that have added ''three'' trials ''total'', this one adds more than double that. This means that there is simply a greater chance that players will be doing one of these for the umpteenth time instead of one that they view as much more interesting, and are ''also'' stuck using their level 50 abilities. Bonus points for when the player doesn't even receive a message of "One or more players are new to this trial" - making one wonder why they got put ''here'' instead of a later trial.

** Deathgaze, the first boss of Dun Scaith, is fought on an airship and the first thing it does as part of its introduction is ''knocking off the rails''. Naturally this means you can fall off. Also naturally this means it'll do attacks that push you back. In addition, [[NotHyperbole every single mechanic or attack]] can potentially wipe the raid if they aren't careful, meaning just about every part of the fight has some level of instant kill danger to watch out for and the mechanics have to be perfectly to avoid dying. It's arguably the hardest fight in the entire raid due to how many ways it can instantly kill you, as well as how it has to be carefully planned out to avoid causing a wipe.