I agree with Jill, please Karen bring back Adam! I'd be happy even if he were only in one paragraph.
I'd love to see Adam in Shadowfever too. However, everybody on these message boards says that Karen says we probably won't see Adam in the Fever series, but we might hear about him. I'm looking at the word "probably" and holding out hope that Karen will surprise us and Adam and Gabby will be present in ShadowF.