We already know that possession oni exist in Ranma's world - after all, there's a manga chapter / OAV episode where Kasumi was possessed by one. It's part of the "fun" of writing crossover stories to figure out how one story's elements affect another story's characters...
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Rob Kelk
"Governments have no right to question the loyalty of those who oppose
them. Adversaries remain citizens of the same state, common subjects of
the same sovereign, servants of the same law."
- Michael Ignatieff, addressing Stanford University in 2012
--
Rob Kelk
"Governments have no right to question the loyalty of those who oppose
them. Adversaries remain citizens of the same state, common subjects of
the same sovereign, servants of the same law."
- Michael Ignatieff, addressing Stanford University in 2012