History ThatOneBoss / Ys

* '' Ys IV'' (the UsefulNotes/PCEngine version) has its BigBad Arem, possibly the hardest final boss outside the remakes. He has three life bars, TurnsRed for his second, can regenerate his HP, it takes [[MarathonBoss an extremely long time]] to whittle down his HP even if your EXP is maxed out, and bombards you with a shitload of hard-to-avoid highly damaging attacks.

'''Note''': {{Final Boss}}es and {{Wake Up Call Boss}}es are not allowed unless they're overly difficult by their standards. {{Bonus Boss}}es are not allowed; they're optional and have no standards for difficulty.

* Nygtilger. Most players won't beat it on their first try. Since it's a SegmentedSerpent, each segment must be destroyed one-by-one first at it moves around the circular arena. The easiest method is to hop onto its back and hack away, but there's only a few scant seconds to do so before it barrels around and charges at players with a hard-hitting electrical attack. Making this worse is every time a segment is destroyed, that part of its body begins spewing timed bombs that have a ludicrously big AreaOfEffect with knockback capabilities, inflicting [[StandardStatusEffect poison]]. Before long, the entire arena will be littered with these bombs, such that players will barely have enough time to swat them away before they explode. Finally, once Nygtilger 's {{Hit Points}} reach less than 50%, it starts rolling around the arena in a lightning-fast motion, a maneuver almost impossible to dodge due to how unpredictable its path is.

* The vampire demon boss (Vagullion) in all versions of Ys I: this boss appears initially as a swarm of bats that can't be hurt, all the while chasing players around the boss arena to damage them. Every once in a while, these bats coalesce into a gargoyle, Vagullion's true form, and players have but a split second to hit Vagullion without taking damage themselves, else the boss turns back into bats, forcing players to redo the entire thing over again.
* The red ape demon in the Famicom port. Jumps around the room firing highly-damaging nearly-undodgeable omnidirectional projectiles. It's nearly impossible unless you [[SequenceBreaking break sequence]] and go further up the tower for the [[InfinityPlusOneSword Infinity Plus One equipment]].
* Dark Fact at the end of ''Ys I'' is a complete son-of-a-bitch; the fight is a BulletHell challenge with non-stop fireballs tracking you everywhere you run at a rate of one every half-second and [[SpreadShot exploding in a spray of smaller fireballs when they hit the ground]], meaning you simply ''cannot'' avoid them all and putting an effective time limit on the fight before your HP inevitably runs out, you have to chase Dark Fact around as he dashes from one corner of the arena to the other, [[HitboxDissonance his hitbox is smaller than it looks]], and even if you can track his (honestly rather simple) movement pattern, every time you hit him ''the ground below you explodes'', not only ''massively'' reducing the amount of actual space you have to maneuver on as you draw closer to beating him (both making it harder to avoid the fireballs ''and'' harder to intercept his movements) but if you don't get off the ground fast enough as it explodes you instantly ''[[OneHitKill plummet to your doom]]''. Matters are made even ''worse'' by a bug in some versions which causes the fireballs to bombard you at an ''insanely'' high rate if you don't manually cap the refresh rate to [=60Hz=], making it all but ''physically impossible'' to win.

* Gruda's OneWingedAngel transformation in ''Mask of the Sun'': not only is this the hardest boss in the game, but it doesn't help that players have to go through a long unskippable dialogue before the battle.

** Orjugan, especially on Hard and Nightmare. It can only be damaged by [[TennisBoss playing tennis with its bombs]], or with the Flame Sword magic, has highly-damaging CombatTentacles, a deadly [[WaveMotionGun super laser blast]] that is difficult to dodge without taking hits from the tentacles (which can kill you instantly on higher difficulties), and finally, periodically summons shadow creatures (which you need to equip the Rainbow Fragment to kill).

This page is about the hardest and most powerful bosses in the ''Franchise/{{Ys}}'' series.

* Khonsclard in ''Ys I'' was largely a LuckBasedMission, but its appearance in ''Ys Origin'' takes the cake: multiple targets, both its main body and several cacti-like {{Mook}}s spawning throughout the arena, the latter of which restore Khonsclard's {{Hit Point}}s if they're not destroyed first. Khonsclard itself fires off plenty of projectiles, all incredibly hard to dodge, the number of cacti-{{Mook}}s increases as the battle progresses, and since the arena is sitting atop of shifting sands that pulls players towards Khonsclard's body, players also have to contend with limited movement options for the duration of the fight. Not even FinalBoss Dalles is as difficult compared to this.

[[folder:Ys: Origins]]