As mentioned in my post about Monster Manual oni, oni have been in D&D since the beginning, but were only called by this name starting in 4e. Before, they were called by the more generic name of “ogre mage”.

There are many different stories about oni in Japanese folklore. The entries here in the MM2 are inspired by by some of them.

All oni in this entry are Natural Humanoids, and all but one are Large. They have darkvision and a signature trait named Deceptive Veil that allows them to appear as any Medium or Large humanoid. Those trying to spot the disguise need to win an opposed Insight test against the monster’s Bluff.

Oni Devourer

Oni Devourer. Copyright 2009 Wizards of the Coast.

These oni are sorcerous tricksters. By day they take the shape of ascetics, beggars and priests. By night they go out hunting for people to eat. Some stories tell of a large group of oni devourers that took over an entire isolated monastery, replacing all the monks and using the disguise to terrorize the neighboring regions. Devourers can also be found in the service of more powerful villains as advisors or “court magicians”.

Devourers are the only Medium oni in this entry, and are Level 7 Soldiers with 78 HP. An Oni Devourer likely approaches its target in disguise using its Deceptive Veil (which only lets them take Medium forms since they’re Medium). Then it uses Hypnotic Glare (Ranged 10 vs. Will) that pulls the target 5 squares and dazes it (save ends). Once in melee range it’s going to use Devour to deal heavy damage and inflict a -5 penalty to the target’s saves, and its basic claw attack to damage and slow, preventing the victim from escaping.

An open fight will likely see the oni in its natural form from the start, but the general tactic will be the same. Despite not having a marking mechanic like other Soldiers they end up being quite sticky with their daze/slow/save penalty combination.

Oni Overlord

In some stories oni aren’t subtle at all and instead lead gangs of monstrous bandits that try to rob and devour any hapless protagonists they come across. Oni Overlords are an attempt to translate those individuals to D&D. They’re Level 12 Elite Brutes with the Leader keyword and 296 HP.

Oni Overlords lead through fear: their Threatening Leader aura (5) gives a +5 damage bonus to all allies inside, but also deals 5 psychic damage to them when they miss all targets with an attack. If you want to mitigate that downside you should give them allies capable of making area attacks. Conversely, if an ally damages an enemy, the overlord can use its reaction for a Violent Reward that gives that ally 5 temporary HP.

While closing to melee range, the overlord can use Overlord’s Blast (close blast 5 vs. Fortitude; recharges when first bloodied) to deal necrotic and poison damage to enemies, and also make them vulnerable to those two damage types (save ends).

Oni Thunderer

Oni Thunderer. Copyright 2009 Wizards of the Coast.

Oni Thunderers seem to be inspired by the myth of Raijin, the god of thunder and storms, who according to the link looked kinda oni-ish and caused trouble as often as he helped.

These oni are extremely strong but not divine. There’s usually nothing good about them, either. They love a fight, and when they get into one they complement their weapon attacks with thunder magic and teleportation. Their weapon of choice seems to be a spiked chain, likely inspired by Raijin’s drum-aura thing. I imagine they usually hang out with other rowdy epic storm-based creatures.

Thunderers are Large Natural Humanoids, and Level 22 Skirmishers with 206 HP. They have dark vision, a ground speed of 8, and a teleport speed of 8 (meaning they can teleport at-will with a move action).

Their oversized spiked chains are Reach 3, do a mix of physical and thunder damage, and pull the target adjacent to the oni on a hit.

Their teleport speed already makes them hard to pin down, and they can use them as part of a Thunderclap Portal maneuver (recharge 4+). This lets them teleport their speed and perform a special attack either before or after that teleport. This is a close burst 2 that heavy thunder damage and pushes all enemies in the area. An enemy who was grabbed by the oni’s chain takes even more damage, though this ends the grab.

When hit by an attack, the thunderer can react with Chain Dance and teleport 3 squares. Finally, they have the same Deceptive Veil power as all the other oni, though they’re unlikely to use it often.

Sample Encounters and Final Impressions

We get a mix of encounters here illustrting the sort of monsters oni might see as servants, equals, or masters depending on their relative power levels.

  • Level 7: 2 oni devourers, 1 oni night haunter, 1 troll. Your typical cannibal giant gang.

  • Level 12: 1 oni overlord, 3 minotaur warriors, 2 scytheclaw drakes. These look more like a bandit leader and his lieutenants, likely running a gang of humans or other smaller humanoids.

  • Level 22: 2 death giants, 3 oni thunderers. Funny, I’d have expected storm giants. But this does prevent the PCs from totally nerfing the encounter with a single damage resistance power.

I like the variety of oni we’re getting here. A large body of legend demands lots of different stat blocks covering different aspects of it.