Oni

As a ""species,"" Oni have a large part played in the history of the known world. The basic knowledge of this is that they claimed right of Rulership from the fey in what's now considered the year 0 OR (Ogre Reckoning but lost control to the smaller humanoids around year 1000 OR (depending on the region). There are still some pure-Oni settlements around, though they're now usually nomadic or well-hidden, and it is known that Oni come in the forms of any intelligent creatures - including the form of the lesser humanoids - which allows these variants to infiltrate settlements or simply live their lives normally.