History ThatOneBoss / FinalFantasyXIV

** 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, 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. 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.

* [[spoiler:Hermes]], from the dungeon [[spoiler:Ktisis Hyperboreia]] wreaks havoc with [[BlowYouAway wind magic]] that, in addition to dealing the usual damage, can toss players around the arena - potentially knocking them into other [=AoE=] attacks and taking even ''more'' damage, or into the outskirts of the arena, where they'll continuously take damage until they move closer to the centre again. Later in the fight, he'll start casting True Bravery (which ups his damage output considerably for his next few attacks), before following it up with Trimegistus, which deals unavoidable damage to all party members. Fortunately, he can be interrupted by stunning him while he's casting True Bravery. ''Un''fortunately, most players probably won't have stunning abilities mapped to their hotbars, since most bosses stopped using interruptable spells after ''A Realm Reborn''. He'll drop meteors onto the field, which the players will need to hide behind in order to avoid a massive blast of air he sends across the arena, then rotate around the rock to avoid the ''second'' blast of air. Not too terrible, except that all but one of the meteor rocks will have cracks in them, causing them to be destroyed after the first blast and leaving players wide open to the second if they picked the wrong rock to take shelter behind. But worst of all? In addition to the usual vulnerable stacks that almost every boss adds to players who fail the mechanics, this boss adds an incurable status ailment to any player who gets hit by his wind strikes, causing them to take significant damage over time until the effect ends, giving healers even ''more'' to deal with in addition to all of the above. Perhaps its appropriate then that [[spoiler:Hermes later becomes Fandaniel, who is controlling Zodiark during the above trial]].

* Phoinix (not to be confused with Phoenix from Binding Coils) is the third encounter in Asphodelos and generally considered the most difficult normal encounter of the tier. Apart from the constant bombardment from abilities in an arena with a colour scheme very similar to the AOE markers, the biggest hurdle is its transition phase. As well as the classic transition charge meter that will wipe the party if you don't clear the phase fast enough, the adds that spawn have a new mechanic: a death overlap radius. A circle indicator appears around the four adds that spawn (two at a time) and persists when they die. If any of the circles are overlapping when the mobs are down and the phase ends, the damage Phoinix does with its charged attack will be significantly increased, doing more damage the more circles overlap. If more than two overlap, it's pretty much a guaranteed wipe. It's very easy for a combination of poorly coordinated tanks and trigger-happy DPS to muck this phase up, either by not understanding the mechanics, poor positioning with the first set of adds that makes it impossible to spread out the second set, or just killing them haphazardly before they're in good positions.

* Svarbanu, from the dungeon Vanaspati, has one particularly unforgiving mechanic in its arsenal. The crumbling sky attack starts out pretty easy but in the second half of the fight, you have to make sure you're blown into the right half of the arena and also ensure you don't bump into the other party members. Ordinarily this wouldn't be so bad but, if you mess it up, the combined damage of standing on the wrong tile and the spread damage ''will'' kill you. If you're doing this with trusts, the way they stand can make it very difficult to work out which way they're going to get blown, and if you die in a trust party you have to start the entire fight over.

* Svarbanu, from the dungeon Vanaspati, he doesn't have many mechanics compared to hermes, but is made up for by just how unforgiving one of his mechanics is, the crumbling sky attack starts out pretty easy but in the second half of the fight you have to make sure your blown into the right half of the arena and also ensure you dont' bump into the other party members, ordinarily this wouldn't be so bad but if you mess it up the combined damage of standing on the wrong tile and the spread damage WILL kill you. If your doing this with trusts the way they stand can make it very difficult to work out which way they're going to get blown and if you die in a trust party you have to start the entire fight over.

** Cuchulainn, the third boss of the Void Ark, is already shaping up as being this. On top of inflicting an uncurable debuff that will slowly but surely sap away at the players' health, he possesses a very wide, lingering AOE that will kill any player caught in it in a manner of seconds (God help you if he accidentally drops one of these on the platforms you need to stand on to avoid his instant-kill attack !), will spawn adds that he can absorb for a significant damage boost, orbs that will need to be exploded before they can explode on their own, often wiping out the raid, or towers that will worsen the constant damage taken by everyone and need to be taken out fast. On top of all this, he boasts a high amount of health and can make himself invincible in certain phases, making him a very grueling MarathonBoss. Compared to him, the actual last boss of the raid is a cakewalk.

** The boss who immediately follows Ozma, Calofisteri. While her pattern and mechanics are much easier to read and predict than Ozma's, she offsets this with her massive range (the entire arena to whichever side of her that her blade is on), her extremely fast casting times (giving players little time to avoid it), and the '''huge''' amount of damage she causes. Now add in the fact that she is constantly planting traps around the arena which can end up forcing unlucky players to get hit by her powerful Haircut attack and you have a boss who ends up getting a higher kill record than Ozma in many cases.
** 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, just about 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. 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.

* [[spoiler:Zodiark]], your ''first'' Trial boss even incomplete as he is, lives up to his reputation of being a serious threat. While his basic attacks that either cover half of the arena or shoot out in a cone aren't too hard to deal with, soon enough he starts trapping the field and then rotating it around without being able to move once he starts the flip -- if you don't carefully position yourself, most [=DPS=] and Healer classes will die. Then he starts weaving multiple attacks together, and it becomes an utter nightmare of balancing and juggling everything at once. He's also a boss that has a repeated attack stack, and it ''hurts''; if your party doesn't have the defenses and the healers don't work the whole time it's going off, people will drop like flies as it hits like an absolute truck. Repeatedly.

* Zodiark, your ''first'' Trial boss even incomplete as he is, lives up to his reputation of being a serious threat. While his basic attacks that either cover half of the arena or shoot out in a cone aren't too hard to deal with, soon enough he starts trapping the field and then rotating it around without being able to move once he starts the flip -- if you don't carefully position yourself, most [=DPS=] and Healer classes will die. Then he starts weaving multiple attacks together, and it becomes an utter nightmare of balancing and juggling everything at once. He's also a boss that has a repeated attack stack, and it ''hurts''; if your party doesn't have the defenses and the healers don't work the whole time it's going off, people will drop like flies as it hits like an absolute truck. Repeatedly.

** This is one of the first times outside of "Extreme" or "Savage" That both tanks have to tank something at once - and spread out. This puts pressure on the healers, who also have to watch the DPS burn down the third add, which is a rarity for this particular game. What's worse is that if the party happens to be squishy (Which is ''very'' likely if the group consists of mostly dancers and mages, which conveniently most groups did) meaning the boss will chew through them like paper and force the tanks to blow cooldowns best reserved for the next phase...

* Suzaku, the boss of the Hell's Kier Duty, is infamous for the difficulty of said fight. For starters, Suzaku has an opening wipe mechanic in the form of phoenix adds that will target the DPS and start attacking, only to charge a powerful AOE attack that, if not stopped, will do enough damage to wipe all but the most geared tanks. The issue is that right when they spawn, Suzaku turns to the DPS and does an AOE attack, forcing them to scatter. Spellcasting DPS can have seriously trouble killing their add as a result, but that isn't the end of it. The adds are also not cleared from the arena when defeated (this is an important note). After this, Suzaku drops large feathers that start charging an AOE, with the goal being to kill the one in the middle for safety. However, if any of the downed adds from before are in one of the AOE pools, they are revived. The party has to kill any revived adds in a short period of time as Suzaku will cast an AOE that is essentially a party wipe if they aren't killed. If you get past that, you have the very easy section where you need to face the direction the arrow is to get a buff and prevent the boss from gaining any more additional damage. After that however, the arena changes to a donut-shaped arena where you can fall off, with Suzaku having the obligatory knock-back mechanics. However, the main gimmick is Suzaku changes the arena into colored sections than summon a phoenix that flies around the perimeter of the arena. Said phoenix flies into colored symbols that match the colored sections of the arena, which causes whatever symbol the phoenix touched to explode the corresponding section.

** 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. 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.
** The third boss fight, 905P-operated Heavy Artillery Unit, however, is a real doozy. 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.

** Cruise Chaser in Alexander: The Heart of the Creator, while unanimously a fun boss with a fun theme, can still be maddeningly difficult due to the coordination the party needs to survive. A large number of his attacks are [=AOEs=], and he can throw out two of them at the same time, or even ''three'' in the later phases of the fight, so anyone unprepared to move at a moment's notice is likely to be killed - and some of these [=AOEs=] are targeted directly at players, so anyone standing beside them is likely to die too. He also spawns several types of exploding adds: a robot buddy that detonates for ''huge'' party-wide damage if it isn't burned down quickly, a pair of canister bombs that can't be destroyed and instead must be hid behind to avoid a mass [[StandardStatusEffects confusion]] attack and will eventually explode for unavoidable damage, and a bunch of "Lapis Lazuli" orbs that must be burned down before he casts his SignatureMove (while also throwing out a [[HPToOne Photon]] before said Signature Move for good measure). Cruise Chaser's ([[BonusBoss optional]]) Savage incarnation is considered even harder than Savage Alexander Prime, exchanging the exploding canisters for ''double'' the [=AOE=] patterns.

* The Puppet's Bunker has two in particular. The second boss fight, or a fight with bosses, has each party in the alliance has a boss. There's several mechanics that can be spilled into the area where the other parties are at. 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. The third boss fight however is a real doozy. 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.

* 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. 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.

* Lightwarden Titania, the first Trial boss of ''Shadowbringers'', earned a fairly infamous status not long after the expansion's release. Their abilities when solo are fairly straightforward, with their most dangerous attack in phase one being a wide cleaving tankbuster that can easily cause deaths if the tank isn't paying attention. The ''add phase'', on the other hand, is very difficult because three adds are summoned and must be killed, except once they are, they're revived with increased size, health, and damage - and the group only has until Titania's Ultimate bar reaches 100 to kill them, or else the party wipes and it's time to start over. Most parties will ''require'' a LimitBreak to deal with the adds in time; the DPS check is tight considering Titania's normal mode is fought relatively early in the Shadowbringers story, requiring players to be aware of how to best deal damage while staying mobile enough to deal with the AoE attacks from both Titania and their summoned adds as well as multiple stacking mechanics. The fight is therefore something of a WakeUpCallBoss for newer players who either coasted through older fights with overgeared parties or else boosted their accounts to 70, skipping all the content that came before.

* Lightwarden Titania, the first Trial boss of ''Shadowbringers'', earned a fairly infamous status not long after the expansion's release. Their abilities when solo are fairly straightforward, with their most dangerous attack in phase one being a wide cleaving tankbuster that can easily cause deaths if the tank isn't paying attention. The ''add phase'', on the other hand is very difficult because three adds are summoned and must be killed, except once they are, they're revived with increased size, health, and damage - and the group only has until Titania's Ultimate bar reaches 100 to kill them, or else the party wipes and it's time to start over. Most parties will ''require'' a LimitBreak to deal with the adds in time; the DPS check is tight considering Titania's normal mode is fought relatively early in the Shadowbringers story, requiring players to be aware of how to best deal damage while staying mobile enough to deal with the AoE attacks from both Titania and their summoned adds as well as multiple stacking mechanics. The fight is therefore something of a WakeUpCallBoss for newer players who either coasted through older fights with overgeared parties or else boosted their accounts to 70, skipping all the content that came before.

* Lightwarden Titania, the first Trial boss of ''Shadowbringers'', earned a fairly infamous status not long after the expansion's release. Their abilities when solo are fairly straightforward, with their most dangerous attack in phase one being a wide cleaving tankbuster that can easily cause deaths if the tank isn't paying attention. The ''add phase'', on the other hand are very difficult because the three adds are summoned and must be killed, except once they are, they're revived with increased size, health, and damage - and the group only has until Titania's Ultimate bar reaches 100 to kill them, or else the party wipes and it's time to start over. Most parties will ''require'' a LimitBreak to deal with the adds in time; the DPS check is tight considering Titania's normal mode is fought relatively early in the Shadowbringers story, requiring players to be aware of how to best deal damage while staying mobile enough to deal with the AoE attacks from both Titania and their summoned adds as well as multiple stacking mechanics. The fight is therefore something of a WakeUpCallBoss for newer players who either coasted through older fights with overgeared parties or else boosted their accounts to 70, skipping all the content that came before.

** 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, there are several instant death mechanics that have to be avoided and the boss has a time limit to kill. 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.

** Angra Mainyu. The first gimmick is the boss does an arena wide AOE where half the arena is light and the other half is dark. At first it doesn't matter which side you stand on. However, this applies a debuff that increases the damage if you stand in the same side again and it'll be a while before its cast again leading to players forgetting which one they stood in (the debuff also isn't too obvious about where you stood in). The second is the boss often shoots out a wide laser beam that causes a lot of damage to anyone not a tank. If the main tank isn't good about staying still or the tanks are fighting for aggro, this causes the boss to wildly shoot this laser, potentially hitting a good number of the alliance. Then there's a look-away doom mechanic that often gets overlooked due to how much is going on and can only be cured by standing in one of the glowing circles. Another mechanic that's instant death involves one player being marked and if a multiple of 3 players are standing in close proximity, they all die when the cast goes off. And finally there are adds that need to be killed, otherwise they explode and do massive damage to the alliance. It's telling one of the ''easiest'' mechanics to do is Roulette, an often derided ability in other Final Fantasy games, which simply marks a quarter of the arena for instant death and if done properly, is easy to dodge.
** Cerberus, the second to last boss from the World of Darkness raid, is the only boss from said raid that the community finds hard, even as late as ''Shadowbringers''. This is because the fight operates under a strange phase system where Cerberus is chained and muzzled, but breaks out after a certain point. While muzzled and chained, he hits hard but mostly seems like a typical boss fight, but once he breaks free, he becomes incredibly aggressive and hard to manage. He has several quick attacks such as an attack where he swings his tail at anyone behind him, a problem with DPS naturally, but he also has an attack where he turns around and charges in a straight line. While the tell for it is easy to see, his cast time is fairly quick, so if you realize it too late, he may just hit you anyway. The main gimmick he has that frustrates people however, is his OneHitKill and how to avoid it: at one point, he'll barf out a purple circle, and spawns an enemy called Gastric Acid, which puts the Mini debuff on the player. The idea is that you get hit with Mini, and then stand in the purple circle, at which point he eats your character and you damage his stomach to weaken him so he can be changed again. However, if you don't have Mini and accidentally step in the purple circle, you get stuck and dragged to the center where Cerberus kills you instantly. Due to these factors, it's seen as harder than the final boss, the Cloud of Darkness.
** The Cloud of Darkness, the final boss, has a few mechanics in particular. The first is she marks a random DPS with an AOE that constantly triggers for a good 10 seconds. The idea is the marked player has to run away from the party, but sometimes this doesn't happen. The second is there are glowing circles that at least one player has to stand in (the so called "meteor" or "towers" mechanic) to avoid it damaging the entire alliance when it goes off, but this can pop up while a lot of action is going on and some of them may be missed. The last is right after her Ultimate, the parties have to go to particular spots to beat up adds. However, a barrier forms around them that locks whoever's in it and keeps others from attacking it. So it's possible that not enough people can be at an add to kill it. Of note, because a majority of the runs usually involve overgeared players, there's a mechanic that's rarely seen due to being skipped: snakes. If they're left alone, they cast Bad Breath or a highly damaging attack, but they can be driven off with any attack. However, since they're rarely seen, it's likely people don't know what to do and thus, the alliance gets crippled.

** Speaking of Alexander Prime, the last boss of the Alexander raid series is notable for a few things (note this happens on the ''Normal'' mode):
*** It shoots out wide beams from its cardinal directions, and the tell isn't immediately obvious to first timers.
*** Its tank buster is a cleave, meaning non-tanks should avoid being in front of Alexander Prime if they can help it.
*** Even its ''auto-attacks'' hurt like a truck, and if the healers aren't paying attention, the tank will die in a short manner.
*** You ''need'' to use the Level 3 Tank Limit Break to survive its ultimate attack. And it needs to be timed just right, otherwise the effect wears off and the party wipes anyway. [[spoiler: If you're having trouble, cast it on the 3 count]]
*** 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 Level 70 Scholar job quest is quite the swerve in difficulty. It's set up like a dungeon boss fight, except you only have one tank and one DPS with you as the healer. This shouldn't be too bad, as the [=NPCs=] can take a fair bit more damage than a player at their level, the boss doesn't hit as hard as a true boss at that level, and you're a healer. The problem is that you and your [=NPC=] allies aren't partied. Because of this you're forced to directly click on the NPC you want to heal instead of selecting their health bars, and the tank is a ''Lalafell.'' Next to the Elezen lancer and the extremely large boss he can be frustratingly hard to target when he needs healing. Also because they're not in your party your fairy, who is a large portion of your healing, won't heal them. Further the boss and its adds have several attacks that are [[GangUpOnTheHuman specifically scripted to target you]] so you have to keep up the healing while dodging multiple [=AoE=] attacks, some of which are exceptionally large. You also don't get the Echo Enhancement if you fail since it's a job quest and not a main story quest.
* Hrodric Poisontongue, the final boss of the Drowned City of Skalla, is notable in that the attacks coming from the boss itself do not show any orange AOE tell. The player has to figure out what it's doing based on its "wind up" animation, which for a MSQ fight, is rare enough that it can throw players off who aren't ready.

* Lightwarden Titania, the first Trial boss of ''Shadowbringers'', earned a fairly infamous status not long after the expansion's release. Their abilities when solo are fairly straightforward, with their most dangerous attack in phase one being a wide cleaving tankbuster that can easily cause deaths if the tank isn't paying attention. The ''add phase'', on the other hand... Three adds are summoned and must be killed, except once they are, they're revived with increased size, health, and damage - and the group only has until Titania's Ultimate bar reaches 100 to kill them, or else the party wipes and it's time to start over. Most parties will ''require'' a LimitBreak to deal with the adds in time; the DPS check is tight considering Titania's normal mode is fought relatively early in the Shadowbringers story, requiring players to be aware of how to best deal damage while staying mobile enough to deal with the AoE attacks from both Titania and their summoned adds as well as multiple stacking mechanics. The fight is therefore something of a WakeUpCallBoss for newer players who either coasted through older fights with overgeared parties or else boosted their accounts to 70, skipping all the content that came before.

** Speaking of Alexander Prime, the last boss of the Alexander raid series is notable in that you ''need'' to use a Level 3 tank limit break to survive its Ultimate on the ''normal'' difficulty. And it needs to be timed just right, otherwise the effect will wear off and you'll have a party wipe anyway. There's also the "Timegate" mechanic that puts players into a 1v1 scenario with a {{Mook}}; if even one of those players dies, it's probably a wipe.

* Trinity Avowed is considered the hardest boss of the Delubrum Reginae raid for several reasons. For starters, many of her [=AOE=] attacks cover a huge area and display their telegraph fields only briefly, giving players little time to avoid them. Getting hit by them more than once results in an incurable [[TimeDelayedDeath Doom]] debuff. Then there is her [[PlayingWithFire Hot]] and [[AnIcePerson Cold]] mechanic, which gives every player a status effect that makes them either too hot or too cold. Players need to balance their temperatures by intentionally getting hit with an attack of the same intensity but opposite temperature, with failure to do so resulting in death. This is made harder by the confusing forms these attacks can take. One form forces the whole party to stay on one end of the arena while the attacks travel down a GhostLegLottery path. Another form has her stand in the middle of the room and slash everything on one side of her with a flaming[=/=]freezing sword: which side she will strike is indicated by her raised sword, which can be difficult to make out against her busy character model. All of these traits add up to an extremely lethal boss where a single misstep can spell your doom.

* The second to last boss of the Delubrum Reginae mini-Alliance Raid, Trinity Avowed, is considered the hardest fight in the raid due to confusing mechanics and short-aoe timers. Her consistently use AOE, Allegiant Arsenal: Bow, is easily telegraphed but the window of time to avoid it is very small compared to what you would expect, making it almost impossible to avoid if you are far enough away from her. The other version of this skill is her summoning copies of herself that attack every tile that she is facing, with only around four spots you can stand on to be safe. The mechanic that makes her super hard though is her [[KillItWithFire Hot]] and [[KillItWithIce Cold]] skill, which causes all players to be marked with a special icon that represents how cold/hot you are. The goal is to make it neutral by standing in the AOE that is the opposite of your temperature but the same amount (so +1 hot means you need +1 cold). The issue is she has three ways of doing this mechanic; the first is a simple case of stand in the AOE, but the second one involves running away after about 90% of the arena is flooded with fire, and you have to move to a specific tile where arrows representing the temperatures will move to. The issue is they move down a GhostLegLottery path, giving you only a split second to figure out where you need to be, making it easy to simply not know which one you needed to go to because you were unable to see it. The last version involves her raising a sword and swinging it on half of the arena, with each swing having a different elemental type and amount, which is not as hard by comparison, but it can be hard to tell which way the boss will attack because of how her model is designed. The Fury of Bozja mechanic alone is enough to make her one of the hardest fights in the expansion, but the other mechanics, topped with the fact you can only take two hits from a mechanic before being inflicted with Doom and dying, makes it incredibly easy to die.

* 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.

* Nidhogg's Shade from ''The Final Steps of Fate''. In an unusual move for Main Story Quest bosses, Nidhogg's Shade is an ENORMOUS spike in difficulty due to the massively damaging aoe attacks which cover large chunks of the arena, smaller aoes which are powerful enough to kill most players in one hit (often using both of these at the same time, trapping players who try to dodge one into getting hit by the other), and a near constant party wide attack which is likely to kill resurrected players due to how much damage it does stacked with the resurrection weakness debuff. In other words, if you die once, you're pretty much out of the fight for good. And Halone help you if you happen to fall before the DPS check halfway through the fight.

* Dun Scaith:
** Deathgaze, the first boss, 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, there are several instant death mechanics that have to be avoided and the boss has a time limit to kill. 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.
** Diabolos, the last boss. 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.

* Hrodric Poisontongue, the final boss of the Drowned City of Skalla, is notable in that the attacks coming from the boss itself do not show any orange AOE tell. The player has to figure out what it's doing based on its "wind up" animation.

* 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.

* While technically it might qualify as a FinalBoss, 4.56 brings us [[spoiler: the resurrection of Zenos yae Galvus, via Ascian]], which involves a very lengthy (if simple) fight where the player takes control of Hien until the Warrior of Light can do their BigDamnHeroes thing. From there, the fight requires a ''hard'' DPS check which is nearly impossible for a lot of classes, a check which outpaces even the aforementioned Sadu fight. And if the player fails the DPS check, they have to do the Hien part ''all over again.'' Thankfully, these days it's a simple task to get gear which makes the check trivial, but upon release it required a lot of grinding or an answered prayer to even have a chance.