History ThatOneBoss / FinalFantasyXIV

** The Idol of Darkness on the seventh floor tended to trip people up with two mechanics. One of them is something the boss does that teleports your character in a certain direction. This isn't so bad the first time around as you just have to make sure you don't fall off the arena. But other times this happens requires you to make sure you teleport in a safe zone due to an AOE about to go off. The second is more of an amalgamation of mechanics. The gist of it is the boss will send four-columns of bird-things across the arena in a certain order. These birds may go into color-coordinated portals. Naturally you have to remember which teleporter was taken in which order to dodge. Then it has a mechanic where the players are given a light or dark debuff and the birds have a light or dark element to them. The player has to be hit with the opposite color. Which isn't so bad until this combines with the portal mechanic and the debuff you have switches to the other color (so a light-debuffed player has to get hit with a dark elemental bird wave, which gives them a dark debuff). The portal mechanic is despised by many in the community because it requires micro-managing knowing what portal connects where, what portal the birds went through, which birds went first, and what element ''you'' have, all at the same time.

** And what's more, once the adds are taken down, 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.

* Captain Madison for Sastasha (Hard) can be hell even for parties that are prepared. Madison will sometimes pick a random party member and shoot them until they die, then switching to another target. Rinse and repeat. Madison will get a damage boost for his gun spam, which makes healing through it impossible. The only way to get him to stop is by having the party damage him enough to knock him out of shooting; if your party isn't properly geared or aware, then it's a guaranteed wipe.

* The World of Darkness raid in general:
** 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. Telling, Angra Mainyu is considered ''the'' hardest boss in the raid, despite being the very first one, and getting past him usually means a group will be reasonably able to get through most of the other fights.

* Shadow of Mhach alliance raid series:
** Remember Ozma, the murderous marble Superboss from ''VideoGame/FinalFantasyIX''? 3.3 brings it back as the penultimate boss of the Weeping City of Mhach, and it is every bit as brutal now as it was then. It rains [=AOEs=] on the party like they're going out of style, it occasionally sticks players with a bomb debuff that is a OneHitKill if they do ''anything'' while they have it, adds will drop in as AOE meteors that need to be carefully place and killed before they self-destruct for raid-wide damage, one of Ozma's forms has exploding energy balls that need to be soaked up by the tanks before ''they'' self-destruct for raid-wide damage, and [[ArsonMurderAndJaywalking it's possible to fall off of the arena]] (thankfully Ozma itself can't kick you off, but you can walk off yourself, so gap-closing skills like Jump and Shoulder Tackle need to be used with care). A single mistake is enough to wipe a whole party, which quickly snowballs into wiping the whole alliance. Its signature Doomsday attack is ironically the ''easiest'' mechanic to deal with since it's only used for a DPS check.
** 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. One of the worst attacks is when it tries to blow everyone off the stage, unless you are standing by an ice barrier. Unfortunately, you have almost ''zero'' warning - so you have to use Arm's Length or Surecast to avoid getting thrown off. An ability which most people probably never even ''bothered'' using. This is also one of the few normal difficulty bosses with an enrage. So even if manage to skirt by through the many deaths, Deathgaze will end up killing the entire alliance anyway after a certain amount of time.
** 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 up. 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.

* Extreme, Savage, Unreal, and Ultimate content is not allowed on this page. These levels of content are considered {{superboss}}es -- they're designed to have more complex and punishing patterns, they're designed to be just for the hardcore rading crowd, and they're all entirely optional in the first place.

* After fighting your way through the Longstop, Titan awaits, and he's a notorious WakeUpCallBoss. Many of his attacks involve pushing you off the edge of the arena, and if fall off the edge, [[OneHitKill you die]]. This is the first boss where such a thing can happen, so new players who aren't expecting such a mechanic are in for a rude awakening. 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.

* The third fight against Ran'jit [[AndNowForSomeoneCompletelyDifferent has you playing as Thancred, who is defending Minfilia]]. This battle 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. 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 at any point while Thancred is invisible, the invisibility will wear off, 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 it really feels like the fight 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 of its difficulty, but because they just want it to be over with as quick as possible.

** The Thunder God in the Orbonne Monastery has a sheer number of mechanics that can catch many first time players off guard. He starts the fight with Cleansing Strike, which brings the entire alliance down to [[HPToOne just 1 HP]] and inflicts Doom, which will kill everyone in 10 seconds unless they are healed back to max HP. The boss also auto attacks all of the tanks at once constantly, so healers from every alliance have to keep on top of healing their tanks. The Thunder God will then use several attacks which requires players to be positioned in certain ways; he can either attack the outermost portion of the arena, the innermost portion of the arena, attack one whole section (circular areas) of the arena, or attack whole sections one by one. Next up, his Crush Weapon attack will mark someone and they have to constantly run away as the attack will follow them and hit multiple times, which will kill the player in 2 or 3 hits if they can't avoid it. Crush Helm has all the tanks suffer Magic Vulnerability Up, which makes the next attack very likely to kill them unless the tanks have their defensive moves popped up and/or the healer removes the debuff in time. Another attack the boss has needs everyone to stand in a circle (3 per circle) to minimize damage from his next attack, which will get a damage increases if there are not enough people standing in the circles. Another attack he'll use involves a mechanic similar to Ozma where the boss will drop an AOE circle on a player and if the circles touch each other, the entire alliance will get hit for big damage and a bleeding debuff. He has a tether attack that contrary to what might seem logical cannot be grabbed by the tank. It is a multi-hitting attack that applies a defense down buff, and one to two stacks of it will cause the tank to be melted by the boss's auto attacks. It has to be passed between the DPS and healers between each strike to be successfully handled. Lastly, the boss will use Crush Accessory where the entire platform is covered in damaging ice and each alliance then has to kill the Icewolves that appear or they'll explode for massive alliance-wide damage. Needless to say, the Thunder God quickly grew notorious for being a PUG killer, so much so that the devs went out of their way to nerf him in Patch 5.21—and even with those nerfs, he can still ruin an unprepared party's day.

** 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. One of the worst attacks is when it tries to blow everyone off the stage, unless you are standing by an ice barrier. Unfortunately, you have almost ''zero'' warning - so you have to use Arm's Length or Surecast to avoid getting thrown off. An ability which most people probably never even ''bothered'' using.

* The boss of the Storm's Crown trial in patch 6.2, [[spoiler:the Empress of Winds, Barbariccia, from ''VideoGame/FinalFantasyIV'']]. The boss starts out by using wide AOE attacks that cover the entire arena, which can easily trip up someone who's never done the raid before. Partway through the fight, the boss will also trap four pairs of players in circles that will heavily reduce their movement speed even while they're in the circle, cause a damage-over-time debuff if they leave the circle, and fire off more AOE attacks while they're trapped. That would all be bad enough, but then the boss goes OneWingedAngel, and that's when the fight ''really'' starts. In addition to harder AOE patterns, the boss sends them out in hectic, rapid-fire fashion. There's no cast bars and no timers for any of these moves, making it something of an InterfaceScrew on top of being punishing. In fact, the boss fires off these moves so quickly that caster DPS classes like Red Mages or Black Mages become nearly unusuable, simply because there's almost nowhere to stand to cast a single spell, much less in a spot that can build up any kind of offensive momentum. Finally, this phase also summons mini-tornadoes that can knock you into the air, which can trigger a chain of them to hit you, leaving you unable to react. And the boss brings back the binding mechanic too, while all of this chaos is flying at you at high speed. There's even a few attacks that you simply can't predict even if you know what you're doing, because where the attacks will fire off is random, so even repeated runs of this boss might catch you off-guard. All this means that the chaotic second half of the fight is one where you can't so much as blink wrong if you're trying to keep yourself or your team alive.

* The Good King Moggle Mog trial, which is required to progress the main story, was so notorious for being obtuse in its mechanics that it had to be reworked ''twice''. The fight has two major phases: the first one is a straight forward Mook phase where you beat down on the King's minions. It's the second phase when the King finally shows up and revives his minions where things could go downhill. In the original version, the minions ''had'' to be defeated in a specific order, otherwise either the party will wipe due to a hard hitting attack or the King will get a buff. Also, the party couldn't attack the King until a certain number of his minions were defeated, otherwise he'll wipe the party anyway. The first rework nerfed the party wiping attack and the buff the King gets so that the order in which the minions were defeated didn't matter as much. However, the King would still enrage if you attacked him too early. The second rework did away with the minions entirely in the second phase, replaced with a mix of mechanics, some of which can throw veterans off who weren't expecting them.
* Captain Madison for Sastasha Hard can be hell even for parties that are prepared. Madison will sometimes pick a random party member and shoot them until they die, then switching to another target. Rinse and repeat. Madison will get a damage boost for his gun spam, which makes healing through it impossible. The only way to get him to stop is by having the party damage him enough to knock him out of shooting; if your party isn't properly geared or aware, then it's a guaranteed wipe.
* Ferdiad, the final boss of Adampor Keep (Hard). At first the fight is simple, but soon you find out the main gimmick of the fight, that he summons adds tethered to him that expands the range of his AOE attack, which pretty much kills everyone except the Tank. While the first time is pretty easy to avoid, you are not out of the woods yet, as he then spawns a slime add on a player that prevents them from moving and needs to be killed before he can do a OneHitKill attack to that party member. Then while attacking he uses several line [=AOEs=] at the same time as summoning a couple of energy scythes that track party members and can easily kill them. And if that wasn't painful enough he does his expanding AOE again, this time with a single very bulky add, and also a couple of the slime adds pinning half the party in place. It gets so bad that most DPS just use their limit break on the bulky add.

* The boss from the Seat of Sacrifice Trial, [[spoiler: the Warrior of Light Elidibus]]. He has a lot of powerful moves that the player needs to be careful of, ranging from fire debuffs that deal tremendous damage if you move, to summoning a Dragon to attack half of the arena. About a third of the way through the first phase, he employs not one but two mechanics that can easily cause a TotalPartyKill. The first is a button-mashing QuickTimeEvent where if even one player fails, the entire party dies. This is followed by the boss using his own LimitBreak, which outright requires a Tank's Level 3 Limit Break as a counter in order to ''barely'' survive it. If the Tanks are new or forget to fire off the LB3, it's another wipe and right back to the start of the battle. Thankfully, there's a checkpoint if you wipe after surviving the boss's Limit Break, though it can be a small mercy considering he adds even more frantic attacks and gets summons that can do even more additional mechanics.

* The boss from the Seat of Sacrifice Trial, [[spoiler: the Warrior of Light Elidibus]]. He has a lot of powerful moves that the player needs to be careful of, ranging from fire debuffs that deal tremendous damage if you move, to summoning a Dragon to attack half of the arena. About a third of the way through the first he employs not one but two mechanics that can easily cause a TotalPartyKill, the first being a button mashing QuickTimeEvent where if even one player fails the entire party dies, followed by him casting a level four limit break where if one of the tanks don't time their level 3 limit just right it is another wipe and right back to the start of the battle. Thankfully after this there is a checkpoint to the fight, though it can be a small mercy considering he adds even more frantic attacks and gets summons that can do even more additional mechanics.

* The meta context during time of release. Boss fights won't have the same experience when overgeared or played in later expansions due to the fluidity of job design, even with Minimum Item Level in effect.

* Extreme, Savage, and Ultimate encounter examples are not allowed. They are considered {{superboss}}es, as they're designed to have more complex patterns for organized play. Unreal trials are essentially remastered Extreme Trials, and thus are identical in battle design, scaled up to match patch content.

** Turn 2 of the Second Coil of Bahamut, also known as Turn 7, is another nightmare. Melusine will inflict random members of your party with Cursed Voice, which petrifies everyone in a cone in front of them after the debuff wears off, and casts her own Cursed Shriek, which OneHitKills anyone who doesn't line-of-sight behind a Cyclops add, who also one-hit kill anyone who gets in range.

** Remember Ozma, the murderous marble BonusBoss from ''VideoGame/FinalFantasyIX''? 3.3 brings it back as the penultimate boss of the Weeping City of Mhach, and it is every bit as brutal now as it was then. It rains [=AOEs=] on the party like they're going out of style, it occasionally sticks players with a bomb debuff that is a OneHitKill if they do ''anything'' while they have it, adds will drop in as AOE meteors that need to be carefully place and killed before they self-destruct for raid-wide damage, one of Ozma's forms has exploding energy balls that need to be soaked up by the tanks before ''they'' self-destruct for raid-wide damage, and [[ArsonMurderAndJaywalking it's possible to fall off of the arena]] (thankfully Ozma itself can't kick you off, but you can walk off yourself, so gap-closing skills like Jump and Shoulder Tackle need to be used with care). A single mistake is enough to wipe a whole party, which quickly snowballs into wiping the whole alliance. Its signature Doomsday attack is ironically the ''easiest'' mechanic to deal with since it's only used for a DPS check.

** 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 [[StatusEffects 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.

* Extreme, Savage, and Ultimate encounter examples are not allowed. They are considered {{Bonus Boss}}es, as they're designed to have more complex patterns for organized play. Unreal trials are essentially remastered Extreme Trials, and thus are identical in battle design, scaled up to match patch content.

* Trinity Avowed is considered the hardest boss of the Delubrum Reginae raid for several reasons. For starters, many of their [=AOE=] attacks cover a huge area and give little warning before they go off. Getting hit with them twice results in an incurable [[TimeDelayedDeath Doom]] debuff that will kill you in seconds. Then there is their [[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 them stand in the middle of the room and slash everything on one side of them with a flaming[=/=]freezing sword: which side she will strike is indicated by their raised sword, which can be difficult to make out against their busy character model. All of these traits add up to an extremely lethal boss where a single misstep can spell your doom.

* 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 give little warning before they go off. Getting hit with them twice results in an incurable [[TimeDelayedDeath Doom]] debuff that will kill you in seconds. 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 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. Also, several players who played the raid shortly after the release of patch 5.55 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''.

* [[spoiler:Hydaelyn]], the last trial before the FinalBoss of ''Endwalker'', 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.

* Hegemone, the boss of the Sixth Circle of Abyssos, is easily one of the hardest fights of the four Abyssos raids. The boss will periodically cast Aetheric Polyominoid to make the tiles of the zone into danger floors, and may also cast Aetherial Exchange to cause the tiles to tether in pairs, and swap just before they fire off. Choros Ixou is an attack which will cover half the arena in a massive blast, which is almost a OneHitKill in terms of damage. There's also Transmission, where the boss tethers to players, and they will be infected with a Glossomorph debuff. At the resolution of the debuff, players will be frozen in place and fire a conal [=AoE=] that reaches across the arena, dealing high damage. It's pretty easy to avoid this by just turning to face the edge of the arena when Transmission fires off, but anyone who doesn't know it's coming is going to be in for a nasty surprise the first time it happens. Finally, there is Strophe Ixou, where the boss rotates and fires off cone [=AoEs=] that either cause Confusion or Bleeding in addition to causing Vulnerability Up. If you're hit by Confusion, you're stuck in place for a few seconds, which will almost certainly mean getting hit by Strophe Ixou more than once, which will almost certainly mean death. And naturally, all of these attacks start to stack as the boss gets lower in health, leaving you with very little room to maneuver and even less time to make decisions about where you need to stand.