Oni
Large Giant, lawful evil
2,900 XP
Special Abilities
Innate Spellcasting
The oni's innate spellcasting ability is Charisma (spell save DC 13). The oni can innately cast the following spells, requiring no material components:
At will: darkness, invisibility
1/day each: charm person, cone of cold, gaseous form, sleep
Magic Weapons
The oni's weapon attacks are magical.
Regeneration
The oni regains 10 hit points at the start of its turn if it has at least 1 hit point.
Actions
Multiattack
The oni makes two attacks, either with its claws or its glaive.
Claw (Oni Form Only)
Melee Weapon Attack: +7 to hit, reach 5 ft., one target. Hit: 8 (1d8 + 4) slashing damage.
Glaive
Melee Weapon Attack: +7 to hit, reach 10 ft., one target. Hit: 15 (2d10 + 4) slashing damage, or 9 (1d10 + 4) slashing damage in Small or Medium form.
Change Shape
The oni magically polymorphs into a Small or Medium humanoid, into a Large giant, or back into its true form. Other than its size, its statistics are the same in each form. The only equipment that is transformed is its glaive, which shrinks so that it can be wielded in humanoid form. If the oni dies, it reverts to its true form, and its glaive reverts to its normal size.
Quick Reference
Running This Encounter
The Oni is a cunning, intelligent adversary that uses magic and shape-shifting to confuse and manipulate the party before engaging in direct combat. It should leverage its ability to turn invisible and cast spells from range, forcing the party to adapt their tactics. Use its high AC and substantial HP to make this a grinding battle of attrition. Consider having it attempt to negotiate, deceive, or separate party members before committing to all-out combat.
Combat Tactics
The Oni prioritizes casting spells like Fireball and Cone of Cold from a distance while using invisibility to reposition. Once engaged, it uses its parry ability to reduce incoming damage and its multiattack to eliminate threats quickly, targeting spell casters first. If bloodied, it may attempt to flee and regroup rather than fight to the death.
Environment & Setting
An Oni thrives in corrupted temples, mountain strongholds, or shadowy forests where it can use elevation and darkness to its advantage. Urban encounters work well in abandoned warehouses or noble estates where the Oni has established a lair.