That One Boss / Kingdom Hearts

"Where's the fun in this?"
Xaldin. Our sentiments exactly.

This page is about bosses in Kingdom Hearts that give away grief like it's candy. Given the fact that there are more bosses in the series than average, it's not surprising some of them made this list. Nonetheless, It's rather ironic that a series that's got complaints lodged at it for being easy has a lot of fans raging about difficult bosses...but nevertheless, even some easy games have sudden difficulty spikes. We need no advice for defeating these monstrosities — that defeats the purpose!

NOTE: A Bonus Boss is supposed to be overpowering, as well as optional, so they don't belong here. The same applies to Olympus Coliseum cups and Mirage Arenas. That One Boss only applies to storyline bosses who are abnormally difficult.

    open/close all folders 

     Kingdom Hearts 
  • In Hollow Bastion, it's frequently a toss up between two fights which occur within minutes of each other:
    • First, Dragon Maleficent. She has a massive amount of health, hits hard, and the location of her one weak point frequently forces you to stand right in her line of fire. Since she takes up so much of the room, there's also a lack of places to dodge and/or hide.
    • The second, Riku possessed by Ansem, is fast and insanely aggressive, with a signature move that can do enormous damage very quickly if not dodged. Compounding the difficulty, you fight him without any party members in an arena that gives little room to maneuver. However, despite all of that, his infamy stems mainly from the fact that in the original release of the game, you couldn't skip the cutscene immediately before the battle, which lasts around two and a half minutes.
  • The first fight with Ursula has a gimmick where you must throw magic at her cauldron to stun her in order to win. Unfortunately, all the game does to explain that gimmick is have Triton warn you about it before you head off, leaving players to flounder around wondering why they can't beat her. Flotsam and Jetsam don't help by getting in the way of your targeting.

    Kingdom Hearts: Chain of Memories 

    Kingdom Hearts II 
  • Despite how Demyx appears to be the Spoony Bard slacker who really doesn't care about anything except playing sitar, you'd be surprised how many people think he fits the description for That One Boss. He seems harmless at first, with attacks that are fairly easy to dodge, but then the timer starts. He creates a batch of water clones, which while harmless on their own, you have to kill within a time limit or lose instantly. This happens multiple times during his fight, and the final round requires you to defeat 10 clones in 10 seconds. Pray they all spawn close to one another.
  • Xigbar is most players' biggest challenge in the World that Never Was, as he's capable of sniping you from a distance, frequently teleports out of your line of fire, and has a nasty Desperation Attack which he uses with increasing frequency as he takes more damage.
  • Xaldin combines high damage, teleporting, impressive reach and the fiendishly hard to avoid Wind Dragon attack. If you ever need to be saved by Mickey, odds are you'll need it here.
  • Roxas (only fought in Final Mix) is fast, unpredictable and hits hard, which only makes sense since he's Sora. It's actually recommended by most players to just avoid him when he tries to initiate Duel. Sure, getting to use his keyblades against him is cool and all, but that doesn't really make up for the fact that now his telegraphed and easily-blocked attacks have been replaced with spamming light beams.

     Kingdom Hearts: 358/ 2 Days 
  • Leechgrave. It has a lot of HP for that point in the story, hits like a truck when you get close enough to hit it, and has four regenerating tentacles that you'll have to deal with repeatedly in order to stun it. Prepare for a long fight.
  • Ruler of the Sky is constantly flying away from you, in a huge arena, and its attacks are nasty when it does come for you. Dying in this fight is especially punishing because of the sheer amount of time it takes to whittle it down.
  • The Infernal Engine combines a tiny arena, Camera Screw, brick-wall defenses, and sheer attack power into one long, difficult struggle.

    Kingdom Hearts: Birth by Sleep 
  • Remember Xigbar? Braig ticks off all the same boxes.
  • Near the end of his story, Terra fights Master Eraqus. The foe is an absolute beast. His attacks are incredibly powerful, and the most dangerous ones come out with no warning whatsoever. Even after you've gotten his pattern down, you have to have the utmost skill to block and/or dodge his attacks, because if you don't, expect three or four hits to kill Terra. Your opponent is also resistant to Dark attacks, and the only Command Style that will activate during this boss is Dark Impulse, so you're at quite the disadvantage.
  • Speaking of Terra's story... Olympus Colosseum. Helmet-less Zack.. When he gets overcharged with Hades' darkness, he's going to let you know what it feels like to be on the receiving end of an Omnislash. It cannot be interrupted. It cannot be blocked. And he uses this as his opening attack.
  • The final boss of Terra's story can quickly turn into this. He has a combo that is just plain unfair: it involves dropping an unblockable meteor which also causes a bright explosion, and then using Ars Solum twice in a row. Even Terra's ultimate abilities won't do you any good. The developers had the sense to program him with the knowledge of your attacks and how to dodge them. Go ahead. Try using Ars Solum, Meteor Crash, or Chaos Blade. He'll perfectly dodge all of them, then smack you down for even daring to try. The only way you're ever going to use his own moves against him is by blocking his attacks (without using Counter Hammer), then taking advantage of a (very) small window of vulnerability by starting off with a regular combo before using said commands.
  • Terranort Phase 1. It is next-to-impossible to land a hit on him under normal circumstances. In fact, there is only one easy way to win the fight, and it takes forever, even if you are at the right level. Combine that with playing as Aqua, and ONLY Aqua.

    Kingdom Hearts Re:coded 
  • Roxas is still a beast. He's ungodly fast, hits like a truck, can inflict multiple stat effects and even his blocked attacks are very hard to punish. Through the fight, he'll teleport around the arena, fire unblockable, homing light pillars while he dashes at you and attacks and will rain down Frickin' Laser Beams once he Turns Red. For extra sadism, when you're almost finished with him, he'll attack with Frickin' Laser Beams (his Final Limit from 358 Days Over 2), only to finish the attack and follow up with even bigger laser beams. It gets better: These beams will cripple your DEF stat if it hits. Get hit once, you take ungodly damage. Get hit twice, you die. Heck, Sora even lampshades this right after you finish the boss fight!

    Kingdom Hearts: Dream Drop Distance 
  • Young Xehanort. Being the penultimate boss and the true form of the Mysterious Figure, he's not easy to begin with, but the real punishment comes when you deplete his first batch of life bars. Fail to pull off a Reality Shift in a tiny window, and he partially revives himself, forcing you to fight him down once more. Succeed and the fight continues, but now he's surrounded by clones which attack almost without pause, using his old moves from when he was the Mysterious Figure. He Teleport Spams, he's open for only a fraction of a second before attacking, and his attacks are blistering fast. That's not all: you now have a time limit to defeat him... or rewind back to phase 1. The True Final Boss is actually easier.
  • Rinzler can be a nasty surprise to anyone who expected a regular Disney villain fight and not a cyber ninja. He's fast, he hits hard both up close and at a distance with a hard-to-predict attack style, and when he flips gravity, the camera doesn't follow suit.
  • You know who's a fun boss? Spellican. The first part of the fight locks you into Flowmotion, meaning no Cures or healing items. Later on you have to do the Flowmotion segment again, almost certainly with less HP to work with. While outside of Flowmotion, he has a variety of painful attacks and a habit of teleporting to hard-to-reach locations and spawning brooms for backup.
  • Anti Black Coat Nightmare's attacks are really hard to dodge/predict to begin with. Then That One Attack drains all but one of your health — and then drops it all over the arena as HP orbs, which the boss can pick up. Luckily, so can you, but taking time out of a battle to pick up your own health does tend to leave a massive opening.

    Kingdom Hearts χ 
  • In mission 425 of Unchained/Union Cross, the player faces Master Ava. This opponent has far and away more HP than any other non-raid boss enemy before them, with over 20 health bars. The boss is also immune to all status effects, alternates between boosting attack and defense every other turn, and increases these boosts even further when HP is low, at which point the boss's boosted attacks are extremely likely to one-shot an unprepared player. Getting through the mission requires patience, luck, and a carefully chosen set of medals that may be difficult to impossible to get without buying lots of them with Jewels.

    Kingdom Hearts 0. 2 Birth by Sleep -A fragmentary passage- 
  • The Demon Tide is quickly gaining notoriety for being a terribly unfair boss, especially at higher difficulty levels. It appears to have practically no consistency in its fight pattern, throwing out highly damaging attacks with seemingly random timing and strange, difficult-to-avoid movements. It also has a frustrating air toss move, which throws Aqua into the air and then summons Shadow balls that are extremely hard to dodge with your limited aerial mobility.