How is 'Kuronue' spelled in kanji? The only place outside of fanfiction I've seen the name "Kuronue" is in Yu Yu Hakisho, so I suspect they made it up. How is it spelled in kanji in the original media? Or is it ever spelled out?
His name is written 黒鵺（くろぬえ）according to the Japanese Wikipedia.

His name means "black chimera." The Japanese chimera is a mythical creature with a monkey's head, tanuki's body, tiger's limbs, and a snake tail.

If you do a Google search for 「黒鵺」, pretty much everything that comes up is about Yuu Yuu Hakusho.