That's a pretty reasonable quick way to do it. If you want, there's always 1e's Oriental Adventures, OA has stats for a few types of oni. Of course, there's always the classic Ogre Magi, and I've done a quick conversion (should be ok to post this, it was always in the SRD):

OGRE MAGI (Blue Oni) (MM + Greyhawk)

Ogre Magi: #E 1d6|AL LE|SZ L|MV 30|DX 8|AC 4|HD 5+2|#A 1/1 (melee)|D 1d12+3|SV 14|ML 8|XP 540|TC G (magic only), R, S|Special:
Regenerate: 1hp per round while alive.
Spells: Can cast fly (self only, 12 turns), invisibility (self only), darkness. Once per day can cast charm person, sleep, and cone of cold (CA 8)
Alter Self: Can change form to any humanoid from 4' to 12', and into gaseous form (as the potion)

Last edited by Carnby (9/10/2023 8:31 pm)

Do you think Oni would be considered giants or would they be more related to mountain apes (ogres)?

rhialto wrote:

I'd opt for mountain apes/ogres for stats, but potentially appearing as just about anything, given their ability to change their appearance.

Id agree. I also remember reading some text (not in Hyperborea) about the Oni and their description being that of Ogres and Ogre Magi. Might have been Oriental Adventures from 2E...
 

Last edited by BlackKnight (9/12/2023 8:33 am)

I like the idea that oni might be the ogre equivalent of an orc in that they might come from the union of ogres and some kind of demon; perhaps a succubus to explain their shapeshifting ability?