I don't recall if the MS oni source was revealed, but there was one in Ravenwood that was summoned there. It was a kind of demon summoned from another place or plane of existence. It didn't sound like it was grabbed out of MS.
In mythology, oni are bad spirits that can look like many things, but have horns, or another feature, that what they appear to be ought not possess, or the wrong number of eyes,ears etc.. We are used to the elephant with horns, but it could be other things, dog with a beak, a duck with eight eyes or fur. Who knows? Feel free to chime in if you know more about this, or if I got anything wrong.
I assume that the oni in Mooshu were summoned there from another kind of existence by magic users. We sure ran into our share of bad wizards that would set such things loose, unless they were able to sneak there on their own with the emperor ill and the elementals unbalanced.
Librarian Fitzhume reminded me that Kogasha has some interesting dialog in the Tower of the Helephant . . . something about the "star-fields of Yago"? Maybe that's a clue? Interesting!
Librarian Fitzhume reminded me that Kogasha has some interesting dialog in the Tower of the Helephant . . . something about the "star-fields of Yago"? Maybe that's a clue? Interesting!
