Sorry I've been gone.
Christmas is awesome but so draining.
I had a couple of vague ideas that you could run with, like if Karoth's tribe notices
The Vanguard going back and forth to the portal they might get curious and investigate, then eventually discover Elysia. They'd probably try to invade again, but I remember Karoth having more, er, civility? So he might help to negate some of the damages bound to happen on both sides. (The barricade isn't finished yet, but Elysia's not nearly as defenseless or unprepared as they were the first time around.)
Another idea is that he's one of the Malaki raiding the Mystriders, and that he somehow meets and gets involved with either Rahil's party (played by David, who are looking for a parasite for Danae. David's on break atm but he might be interested) or Jericho and Alistair (played by myself and Lau respectively) who are attempting to forge economic relations with Vynett.