History Characters / TheBindingOfIsaacFinalBosses

* BulletHell: ''Rebirth''[='=]s version shoots red tears nearly constantly throughout the whole fight, even when retreating to the back of the room.

* ClimaxBoss: It Lives! is one for a majority of the routes[[note]]aside from the Corpse, the Ascent and the Void (if the portal spawns after Mom), which you already cut yourself off from by progressing to the Womb and variations[[/note]], as it provides the branching routes that lead to the final levels, all of which are points of no return. In the Mother route, Mausoleum/Gehenna Mom's Heart takes up this role.

* OffModel: The Lamb's portrait in the versus screen is dark in color, but in-game and in the ''Afterbirth†'' trailer, The Lamb is coloured white.

* SequentialBoss: Subtler than most, but she has two distinct phases. First she alternates between chasing Isaac and stopping to perform various attacks. Once she's half dead, she drops all other attacks and only moves across the screen.

* OneBadMother: Described as the "Mother of Harlots" and is the ''true'' TrueFinalBoss.

* EvilOverlooker: Its boss portrait has Mother looming over Isaac in this fashion, instead of the "facing Isaac from the side" view of every single other boss.

* TeleFrag: Like ???, he likes to teleport either very close to or right on top of you, almost guaranteeing damage unless your reflexes are faster.

* BraggingRightsReward: Besides unlocking the final and definitive ending, there is no reason to fight him other than to boast you did it. The only thing you get out of winning is a new picture for your save file. There are no associated items or character unlocks, not even a mark on the character file to indicate that character beat him. This has since been [[AvertedTrope averted]] with ''Afterbirth'', as he now has his own completion mark with unlocks tied to it, in addition to counting towards the co-op baby (or Godhead, in The Lost's case) unlocked by getting all completion marks for a character on hard mode, '''and''' beating him once with every character unlocks the Mega Blast item. ''Afterbirth†'' adds another with Booster Pack 5, where defeating him once now unlocks Apollyon.

* CognizantLimbs: His hands.

** Ultra War drops the guitar in favor of oppressive drum beats and percussion.

* FanDisservice: [[https://bindingofisaacrebirth.gamepedia.com/File:Boss_Ultra_Greed_back.png Has a large, visible, and well-detailed butt]]. He's also a massive corpse-like monster that ultimately has a little boy as the base of his design, and might even ''be'' an alternate version of a little boy.

* RedIsViolent: Both of them are red bosses.

* SayMyName: Satan's battle cry when you defeat his first phase is Mom's BossBanter, only lower pitched and in reverse. [[ChekhovSGun This become much more important later when Isaac encounters]] [[BeastOfTheApocalypse The Beast]].

* HumanoidAbomination: Most of what she does in-game and in a few cutscenes blatantly disregards normal body movements if not physics. She can step on her own eye, generally alter her size, and her arm can fit in a chest inside her heart inside her womb.
* KevLard: A textbook FatBitch with rather high health.

* RuleOfSymbolism: All of Delirium's unlocks on the Tainted characters except for Isaac [[note]]covered by the Soul of Isaac after [[SpeedrunReward clearing Boss Rush beating Hush]][[/note]], the Lost [[note]]covered by Sacred Orb after beating the Beast[[/note]], and Keeper [[note]]covered by The Hanged Man? after beating Ultra Greedier[[/note]] are items that allow any other character to use one of their gimmicks. The implication, of course, is that if the game is a DyingDream, all the possible choices that can be made in a run don't matter, since it's all the same story of Isaac's suicide.

->Debut: ''The Binding of Isaac''

* AmbiguousGender: The Beast's gender isn't specified in-game, even during the cutscene taking place after the battle. It's possible that it's female, however, as the narrator in the ending refers to it as "the Mother of Harlots", and it wears a tattered form of Mom's dress. ''Four Souls'' promotional material resolved this by referring to the Beast with feminine pronouns.

* TheThingThatWouldNotLeave: In ''The Binding Of Isaac: Four Souls'', most of the final bosses from the main game are worth 2 souls, but [[BonusBoss Delirium is worth none]]; instead, he has the gimmick that when he dies, he goes back into the monster deck, four cards down from the top. This means that once Delirium shows up, he'll constantly keep returning, no matter how many times he dies, unless extremely specific measures are taken to bury him deep in the deck again.

* RuleOfSymbolism: All of Delirium's unlocks on the Tainted characters except for Isaac (covered by the Soul of Isaac after beating Hush), the Lost (covered by Sacred Orb after beating the Beast), and Keeper (covered by The Hanged Man? after beating Ultra Greedier) are items that allow any other character to use one of their gimmicks. The implication, of course, is that if the game is a DyingDream, all the possible choices that can be made in a run don't matter, since it's all the same story of Isaac's suicide.

* EleventhHourSuperpower: Dogma itself is one. After its defeat, it grants its power to Isaac, giving him flight, damage resistance[[note]]Though only in Normal Mode. It behaves the same was as The Wafer[[/note]], a one-time Holy Mantle effect, a damage upgrade, refilling all of Isaac's red hearts, and giving him soul hearts if his max life is fewer than six. ''[[SuspiciousVideoGameGenerosity You will need it!]]''

* EleventhHourSuperpower: Dogma itself is one. After its defeat, it grants its power to Isaac, giving him flight, damage resistance (same effect as The Wafer), a one-time Holy Mantle effect, a damage upgrade, refilling all of Isaac's red hearts, and giving him soul hearts if his max life is fewer than six. ''[[SuspiciousVideoGameGenerosity You will need it!]]''

* {{Superboss}}: In ''Four Souls Requiem'', it is the only other [[NintendoHard Epic Boss]] besides Delirium that does not grant souls upon defeat.

* ShesGotLegs: Inverted. The game gives us a detailed sprite of Mom's leg, and it's textbook FanDisservice.

* SayMyName: Satan's battle cry when you defeat his first phase is Mom's BossBanter, only lower pitched and in reverse.

* ThePawnsGoFirst: Isaac must defeat her minions, the Harbingers (sans Headless Horseman and Conquest), before he can take on the Beast itself.

* DefeatEqualsExplosion: Besides the usual "[[LudicrousGibs burst into gore]]" death effect that most bosses have, Ultra War explodes more traditionally upon death — which can hurt Isaac if he's too close.

* BossBonanza: They collectively have a total of 7800 HP[[note]]Ultra War, Ultra Famine, and Ultra Death each have 2,000 HP while Ultra Pestilence has 1,800 HP[[/note]], which is even more than Hush and Mega Satan. And they're the ''in-between'' bosses between Dogma and The Beast. The only reprieves Isaac has is the Ultra Harbingers having significantly weaker boss armor than Hush or Mega Satan, and each fight being treated as a wave (just like Challenge Rooms and the game's own BossRush), so any room-clearing effects will proc here.