Main Character Final Boss

When it comes to heroes, it cannot be denied that some end up with a set of powers that by all means should make them god-like in terms of power. Much like a god, it becomes terrifying when The Hero of the story finally snaps or succumbs to their personal issues, is Slowly Slipping Into Evil, is corrupted by an artifact or being possessed by the Big Bad or their powers end up spiralling out of control, etc. Their allies (if any exist) are now forced to deal with a threat more powerful than any other and one who is very close to their hearts. Depending on the story, their allies may get through to The Hero and revert them to normal or be forced to deliver a Mercy Kill to save everyone else or something in between.

The main character doesn't have to become a villain for this to happen, though some main characters do undergo Big Bad Slippage or start Slowly Slipping Into Evil which may cause them to become the final boss of their own story.

What qualifies as a Main Character Final Boss:

• The protagonist(s) and the final boss must be the same character in the same story.
  • If the protagonist becomes an antagonist in the sequel, they are a Rogue Protagonist but if they retain their heroism but not their main character status that's Dueling Player Characters, Hero of Another Story, or Previous Player-Character Cameo.
• The main character is playable throughout the game but for this fight is no longer playable. Any characters you do play as either their allies or any available characters. If you're controlling the Main Character Final Boss, it's either Role-Reversal Boss or Play as a Boss.
• If main characters are the final boss in each other's stories but not the final boss of the entire game, then it's Dueling Player Characters.
• For non-video game examples, the story must either no longer take place from the main character's perspective or if it still does, show the main character's warped perspective.
• If the main character is evil by story's end, the story must either end with them returned to the side of good, killed, or anything in between. If the character survives and stays evil, then any sequels or continuations no longer count as Protagonist Final Boss unless they are a Villain Protagonist.

What doesn't qualify as a Main Character Final Boss:

• If the final boss resembles the protagonist but isn't actually them, it's either an Enemy Without, Evil Knockoff, or a Mirror Boss.
• If the final boss also shares traits from the main character or is a foil to them, that's either Evil Counterpart, Mirror Character, or Shadow Archetype.
• If the final boss consists of the players fighting each other in multiplayer, it's either Dueling Player Characters, Player Vs Player, or Mirror Match.
• Superbosses are disqualified because they aren't final bosses by definition and because most protagonist superbosses tend to fall under Previous Player-Character Cameo and Dueling Player Characters.

Compare Dueling Player Characters or Player Vs Player, contrast Rogue Protagonist or Role-Reversal Boss. For possible catalysts see And Then John Was a Zombie, Demonic Possession, Despair Event Horizon, or Superpowered Evil Side. For the end results, see Cooldown Hug, "I Know You're in There Somewhere" Fight, I Cannot Self-Terminate, or Mercy Kill.

SPOILER WARNING: This is a Spoilered Rotten trope as every example is a protagonist turned final boss by the end of their story or series, and in some cases may involve death all of which contain unmarked spoilers. You Have Been Warned!

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Examples

Anime & Manga

• Attack on Titan: Eren becomes the Big Bad after he convinces Ymir Fritz to give him the full power of the Founding Titan, intending to wipe out all of civilization outside of Paradis Island so they won't exterminate his people, and it's revealed that he's been planning this all along via a Stable Time Loop by influencing the previous wielders of the Attack Titan's power. The endgame revolves around Eren's former comrades teaming up with Marley's remaining Titan Shifters in order to put a stop to him.
• Demon Slayer: Kimetsu no Yaiba: Both Tanjiro and Muzan die during the climax, but the latter resurrects the former's body as a demon before sending him after the Demon Slayer Corps. They end up having to fend him off until Kanao applies a serum that reverts Tanjiro back to normal.
• Dragon Ball: The end of the Pilaf saga sees Goku's first on-screen transformation into a Great Ape, which breaks the gang out of the prison that Pilaf has placed them in following their thwarting of his plans... but since Goku has lost his ability to distinguish friend from foe, now they have to figure out how to change him back before he kills them anyway.
• Puella Magi Madoka Magica The Movie: Rebellion: Homura is the main protagonist of the film, due to it taking place after the original series which ended in Madoka being erased from existence after her ascension to godhood. During the film's climax, it's revealed that the witch controlling the Mitakihara witch barrier is Homura's own witch form Homulily. Even after defeating the witch, Homura succumbs to her madness and steals Ultimate Madoka's god powers to become Devil Homura, and creates a new world where Madoka will never be harmed again.
• RahXephon: Ayato Kamina ends up becoming the final boss of the show after he merges with Ixtli and becomes the True RahXephon. During this time, his song ends up killing off several characters and when Quon appears to him in her own ascended form, it's so they can merge together, allowing Ayato to rewrite reality so that the Mulian threat never existed and all Mulians could live normal lives as humans.
• Yu-Gi-Oh! has had quite a few over the years:
  • Yu-Gi-Oh!: The last duel is between Yami Yugi and Yugi, as Yami Yugi wants to go to the afterlife and see if Yugi can manage without him.
  • Yu-Gi-Oh! ZEXAL: The last duel is between Yuma and Astral.
  • Yu-Gi-Oh! ARC-V: The Greater-Scope Villain of the anime is revealed to be Zarc, who is the original self of protagonist Yuya and his counterparts Yuto, Yugo, and Yuri. Prior to being fought - by the entire cast except those four - he made several "appearances" by having his personality energy through Yuya during extremely stressful or high-pressure duels - essentially giving the audience a Final Boss Preview to showcase how ruthless, violent, and controlling he is during duels.

Comic Books

• The Boys: Billy Butcher, leader of the titular protagonist group, ends up as the final boss of the series after going off the deep end and killing every member of The Boys except for Hughie, and intending to do the same to anyone with Compound V in their blood. Hughie has no choice but to kill Billy to prevent Billy's genocidal plan from coming to fruition.

Fan Works

• Flawed Crystals: The final boss is Steven Universe himself after succumbing to his corruption. Your party members can fight Steven and eventually kill him, but doing so nets you the bad ending. The Talk option plays a key role in this battle, and each character has dialogue choices they can choose from. If they try to plead with Steven and use the Power of Love, Steven will insult your party members in ways personal to them and that party member ends up getting debuffed. However, if you choose to call Steven out on his cowardly and selfish fantasties he created in Rose's Room, Steven will feel awful and you'll be a step closer to freeing him from his corruption. Once all party members have called Steven out, he'll spam Dying of the Light on your party with only Jasper maintaining her form out of sheer determination. At this point, you can still kill Steven or have Jasper show empathy which will allow Steven to be free of his corruption.
• Psychic Puppets: Mewtwo is the main protagonist throughout most of this ROM hack but after his partner Pokémon reveals themselves to be Mew in disguise and Mewtwo subsequently teleports away out of betrayal, the playable role is swapped between the two for the rest of the story. By the time the partner finds Mewtwo at the end, the latter resorts to fighting them to force them to go away, serving as the last challenge.
• Pony POV Series: Nightmare Eclipse is the final boss of the Dark World arc. She is a future version of Twilight, a corrupted alicorn who has learned time magic and is using it to keep the Dark World timeline in a 1,000-year "Groundhog Day" Loop to punish Discord — the former Big Bad — for all eternity. Every time the current Twilight and her friends have defeated Discord, Nightmare Eclipse finds some way to corrupt that Twilight into another Nightmare Eclipse, absorbs her to increase her own power, and then begins the loop again with new versions of Twilight and her friends. After defeating her and finally breaking the loop, Twilight fuses with her to become a fully ascended alicorn: Princess Amicitia.

Film — Live-Action

• Fantasy Island (2020): Melanie is presented as the protagonist but in the end she wants to kill all the people in the island.
• Star Wars: Revenge of the Sith has Anakin Skywalker gradually become more corrupt due to Emperor Palpatine playing on his fears of Padme's death. By the end of the film, Anakin has killed several younglings and now intends to rule the galaxy as Darth Vader. After a climactic fight, Anakin loses his limbs and is left to die by Obi-Wan, ensuring Anakin is Doomed by Canon to become Darth Vader, the iconic villain of the Original Star Wars Trilogy.

Live-Action TV

• Dexter: New Blood: Dexter is the villain protagonist of both Dexter and its sequel series, New Blood. New Blood ends with Dexter as the final boss, and he is killed by his son Harrison after murdering Logan to escape justice for his crimes. However, Dexter allowed this to happen so that his son could live a life free of Dexter's crimes; it's also implied that he would eventually be revealed as the Bay Harbor Butcher.
• Game of Thrones: An interesting case. The show slowly consolidated its cast until it was following three storylines and had a protagonist or two for each, with Jon Snow in the North, Jaime Lannister in the South, and Daenerys Targaryen in Essos, eventually culminating in all parties meeting and (briefly) allying to fight the Night King. Once the Night King is dealt with, however, the show frames Cersei Lannister as the final villain, only for Daenerys to dive headfirst off the slippery slope in the runup to the Battle of King's Landing and completely ransack the city, killing innocents and burning the city to the ground, making her the show's true last antagonist that Jon has to kill.

Video Games

• BLUE REVOLVER: If playing on Parallel and you meet the conditions to fight the True Final Boss, or rather, the True Final Bosses, your opponents will be Dee (the regular Final Boss) and whichever of the two player characters you didn't pick.
• In Breath of Fire IV, if Ryu agrees to merge with Fou-Lu, he becomes this and fights his former teammates.
• Bloodstained: Curse of the Moon: The main playable character, a demon hunter called Zangetsu, is possessed by the final boss at the end of the game. If the player had opted to recruit Miriam, Gebel, and Alfred before then, a new campaign called Nightmare Mode will be unlocked. It consists of those three characters joining forces to break the curse, which culminates in a climactic final battle against their former friend.
• Castlevania: Dawn of Sorrow: In a unique twist on the extra character modes which had become series standard by this point, Julius Mode is unlocked via the bad ending, and continues on from it. In the bad ending, Soma fully embraces his inner darkness and becomes Dracula, upon which Julius, Yoko, and Alucard resolve to stop him. Julius Mode swaps to the perspective of Julius and his companions, and upon making it to the centre of the Abyss, they confront Soma and are forced to fight him as their final enemy. In a rather dark take on this trope, not only are they forced to Mercy Kill Soma, there is also the implication that he will eventually resurrect fully as Dracula, starting the vicious cycle all over again.
• In Cry of Fear, the final boss is either the imaginary Simon that the player has been controlling throughout the game, or the real wheelchair-bound Simon, depending on earlier choices.
• Contact: The player character Terry finally figures out that you've been controlling him all game and decides he isn't gonna have any more of it — requiring you, the player, to stylus-tap him into submission. Fortunately for you, Terry himself is a Zero-Effort Boss because he has no actual means to fight back.
• An interesting case happened in Dragon's Dogma. Savan starts out as a Decoy Protagonist and then we find out that he has become something of a deity and becomes the final boss. If you play on New Game Plus, the character you played previously will be the Final Boss.
• Eternal Sonata: Frédéric himself becomes the final boss of his own game due to his realization that the entire world he's in is simply a dream undergoing a Stable Time Loop and that he's actually dying in the real world. You get a different ending depending on if your party wins against him or loses to him.
• The Last of Us Part II: It's played straight at first with the end of Abby's three-day plotline concluding with a boss battle against the game's main protagonist Ellie. After a Time Skip, it's zigzagged as the protagonist Ellie then pursues Abby to California, and her final battle is Abby.
• The Legend of Dark Witch has Zizou play the role of both main protagonist and final boss in most of her games. This is averted in the Brave Dungeon games where she's a Superboss instead.
  • The Legend of Dark Witch has Zizou as the main protagonist and final boss (of Riva's story), winning out in both her and Riva's endings (using blackmail to force Riva to stand down after getting her ass kicked)
  • The Legend of Dark Witch 2 has Zizou as the main protagonist and final boss (of Sola's story). Unlike the previous game, she simply accepts her defeat simply because Sola isn't a villain (and Zizou had already taken care of the Big Bad anyway.)
  • The Legend of Dark Witch 3 has Zizou as the main protagonist and final boss (of Day's story). After being defeated, Zizou lets her sister Mati fight Day instead of attacking with her full power. Justified because it's implied that Zizou had already taken care of Simeone like in her story and that she and Mati were stalling for time until Day's friends arrive to convince her to stop her quest for revenge.
• In Library of Ruina, the two Downer Ending routes have main character Roland as the Black Silence acting as the final boss, revealing himself to have been planning Angela's destruction as revenge ever since the start of the game, and that his friendly, carefree attitude was merely a facade. The Golden Ending route, however, subverts this as Angela and Roland forgive each other and the True Final Boss is a One-Winged Angel rematch against the Reverb Ensemble.
• Live A Live: Oersted, the protagonist of the unlockable chapter "The Middle Ages", loses everything at the end of the chapter after being betrayed by the people he thought were his friend and lover. He then calls himself "Odio" and vows to take revenge on mankind, sending an incarnation of himself bearing the name "Odio" as the final boss of the previous chapters. He also appears in the Final Chapter "The Dominion of Hate" as either the protagonist who sets out to Make Wrong What Once Went Right by taking control of the other bosses or as the final boss of the game. The HD-2D remake adds a third form for the final boss called Sin of Odio, which allows Oersted to finally redeem himself by separating himself from the embodiment of his hate and being the one to destroy it.
• MADNESS: Project Nexus 2: Hank, the protagonist of Project Nexus and the Madness series in general, becomes the final enemy for Sanford and Deimos to fight after pulling a Face–Heel Turn and seeking to destroy Nevada.
• Mana Khemia: Alchemists of Al-Revis: The main protagonist Vayne Aurelis has powers that are very destructive, enough so that they can warp reality. If the player spends the entire game making Vayne antisocial and sleeping away all their free time instead of doing quests to strengthen bonds with other party members; they'll be on route to the bad ending route where he himself is the final boss. On the good ending paths, Vayne is only the first form but is eventually freed so he can fight the Crazed Eye -the embodiment of his power- as the second form of the final boss.
• Middle-earth: Shadow of War: At the end of the Blade of Galadriel DLC, previous player character and protagonist Talion, after spending most of the game working alongside new player character Eltariel, and helping her defeat the rogue Nazgul (in addition to spending literal decades earlier fighting and dividing the Orcs of Mordor to prevent either Sauron or Celebrimbor uniting them to take over Middle-Earth), finally falls to the corrupting will of his Nazgul Ring of Power (helped along by lingering anger and resentment towards Eltariel for being the reason why he's a Nazgul now), and turns against his former friend and starts fighting her. Talion is the final enemy you have to fight in that DLC, solidly reminding players that the hero we once knew is no more.
• Midnight Suns: For the final boss, the custom main player character is possessed by the Big Bad, forcing the player to control the remaining heroes to defeat them.
• OFF: This is played straight if you choose to betray The Batter in favour of taking The Judge's side. For the entire game, you played as The Batter and have been helping him to purify the world, even as the dark implications of your holy task are brought to light. During the final boss fight, The Batter's final boss state is portrayed as a monstrous creature with an elongated mouth filled with teeth. However, if you choose to follow through with your holy quest to purify the world and side with your puppet until the end, this trope is averted.
• OMORI: After Omori realizes he can no longer hide the truth about Mari's death from Sunny he goes all out, attacking Sunny and trying to make him take his own life.
• In 200% Mixed Juice, the final bosses are Protagonist and Navi, better known as Suguri and Sumika, who are respectively the nominal main protagonist and Fairy Companion.
• Puyo Puyo Tetris: Tee is the main protagonist on the Tetris side, being introduced as a calm and stoic character who is very good at Tetris. Come the seventh chapter (which is the final chapter of the main story), and he wants to take Ex's place as Keeper of Dimensions, his reasoning in the Japanese version being him thinking that it would be better if he'd be trapped instead of Ex. The final battle has you playing as Ringo as she battles Tee to snap him out of this mindset.^note You do have to fight Tee as the final boss again in the tenth chapter, the last of the DLC chapters, but 1) This takes place in a dream, and 2) This is a reenactment of Tee and Ex's first meeting back when the latter was the Tetris King.
• Sonic Battle: While each chapter of story mode gives major focus on a specific character, Emerl is the main protagonist of this game specifically due to being the main focus of the story and whose colours and moveset can be customized to the player's liking. Come his chapter, which serves as the final chapter, Eggman causes him to malfunction from the power of the emeralds, resulting in him serving as the final boss of the story.
• South Park: The Fractured but Whole: Downplayed. The first phase of the final boss is the New Kid's past self in their King Douchebag persona from the previous game, South Park: The Stick of Truth, accompanied by Clyde, Craig, and Kyle (and, during the last phase, Butters), which is often considered the hardest boss in the game. The real final boss, present Cartman and Kyle using the former's Mitch Conner persona, is more of a Post-Final Boss in comparison.
• Spark the Electric Jester 3: After being filled in on the details by Fark regarding Clarity and the fact that Spark had inadvertently caused Clarity to successfully assimilate the entire planetary population into her simulation in addition to finding out his entire adventure was a "Groundhog Day" Loop, Spark snaps and ends up becoming Linework Spark. It takes Fark defeating the corrupted Spark to free him, and then after the two fuse, they proceed to take on the Clarita Centralis.
• Touhou Project:
  • In games with versus mode, each playable character has a story route, including the usual Final Boss. They then usually fight series protagonist Reimu Hakurei as their final opponent, making her the True Final Boss of the game. This happens in Touhou Suimusou ~ Immaterial and Missing Power, Touhou Kaeidzuka ~ Phantasmagoria of Flower View, Touhou Hisouten ~ Scarlet Weather Rhapsody, Touhou Shinkirou ~ Hopeless Masquerade, and Touhou Juuouen ~ Unfinished Dream of All Living Ghost.
  • In Double Spoiler ~ Touhou Bunkachou, you play the entire game as Aya, except for the final level. In the first three rounds, you still play as Aya fighting new character Hatate. But in the last three rounds, you fight Aya as Hatate instead. After this, you unlock the ability to play as Hatate in previous levels.
  • In Hifuu Nightmare Diary ~ Violet Detector, you're playing as Sumireko who is trapped in a dream, fighting against the other characters' dream selves. In the final level, it's revealed she's actually Dream Sumireko who mistakenly believes she's the real one. The real Sumireko appears in the last level, and then you play as her to fight the Dream Sumireko.

Western Animation

• My Little Pony: Equestria Girls – Friendship Games: Downplayed. Human Twilight Sparkle, the Alternate Self of Princess Twilight Sparkle (protagonist of the parent series My Little Pony: Friendship Is Magic and the first two Equestria Girls films), is set up as the Deuteragonist, as she is the most sympathetic of the Crystal Prep students, has an arc about discovering magic and friendship, and slowly becomes friends with the main cast. But Peer Pressure Makes You Evil plus Curiosity Is a Crapshoot causes her to unleash the magic she's been inadvertently collecting, turning her into the mad-with-power Midnight Sparkle. Sunset Shimmer and Spike manage to turn her back with an "I Know You're in There Somewhere" Fight.
• OK K.O.! Let's Be Heroes: The last opponent is T.K.O., K.O.'s Superpowered Evil Side gone rogue.
• Steven Universe: Future: The combination of everyone no longer needing him, Steven's own crisis about what he's supposed to do now that everyone no longer needs him, and his bottled-up trauma from the entire franchise causes him to spiral into a complete mental breakdown where he sees himself as a monster — and because his powers are so entwined with his emotional and mental state, this causes him to turn into an actual monster, blinded by rage and completely unable to be reasoned with. It takes his family restraining him in a hug and reaffirming to him that he's not a monster for Steven to return to normal.

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