Well, if she kills Richard, she has to change cannon, as part of the triumvirate, killing him should kill them all. It's happened in other books, where killing one member of a triumvirate kills them all.

Micah is 'Nimir Ra' which isn't really a supernatural bond as strong as the bond with JC/ Richard. Nathaniel is just her boytoy. Jason is her fuckbuddy. So any one of those three would not have a major impact, although there is the minor triumvirate of Nathaniel/ whatshisfacetheredhead/ Anita. She's pulled 'major metaphysical' on that triumvirate several times already.

I really hope it's not Edward - I still maintain Edward would kill Anita. If it was the serial killer she wouldn't be angsting.

Maybe it's Ronnie, her favourite whipping girl.

I pretty much stopped reading after 'Cerulean Sins', so no doubt other people have cropped up.