Mortis, the Bone Tyrant

Boss

Fought on floors 40 and 50, in Act 3: The Undead Halls. Floor 50 is this act's climax fight.

Mythic, cursed, and divine relics sit above legendary, the fusion ceiling, and drop only from boss and guardian kills: mythic from floor 50, cursed from floor 80, and divine from floor 90. Here, a mythic relic can drop from its floor 50 kill.

Abilities

Frostball

Targets all-enemies · 4-turn cooldown

Blasts all enemies for magic damage and may stun them.

• damage, power 10 + 0.9×magic
• status, applies Stunned (stun, 1t)

Poison Arrow

Targets enemy · 2-turn cooldown

Strikes one enemy and poisons it; re-applying refreshes the duration.

• damage, power 8 + 0.8×attack
• status, applies Poisoned (dot, 3t)

Heal

Targets ally · 2-turn cooldown

Restores a large amount of hp to one ally.

• heal, power 14 + 1×magic

Statuses It Inflicts

Inflicts: Stunned Poisoned

How to Prepare

• You fight Mortis, the Bone Tyrant solo, and there is no rest heal before the encounter, so arrive with real HP in the bank and sustain already flowing: lifesteal earned in the fight itself, plus potions bought with gold beforehand.
• An escort wave of the biome's regular enemies fights first. Only after they fall does Mortis, the Bone Tyrant step out alone for the closing wave, so keep enough HP and cooldowns in reserve for the real fight.
• Its kit includes a heal. It fights its own wave alone, so that heal restores its own HP: bring enough sustained damage to outpace it, not just one big burst.
• It can stun you, skipping one of your turns outright, so don't fight this one on a razor-thin HP margin.
• It can inflict Poisoned, damage that keeps ticking after the hit lands, so don't count only your burst; a dragged-out fight bleeds you too.
• If you wipe, you restart at floor 1, but your permanent upgrades and talents carry over, so a loss here is a setback, not a full reset. Optional Hardcore mode also destroys your equipped gear on a wipe.