Find the mob A wily rogue (is trackable) and abjure him via the spell, a scroll or high level item. If bringing scrolls, bring several - they are not a guaranteed success. Recommended to bring an archon or high level character who knows what they are doing. Low level characters should be wary of venturing into New Kolvir alone, as it is easy to get lost and the rogue has been known to go down into the moat which is underwater and full of aggro mobs that will kill you quickly if you do not know what you're doing. It's easy to accidentally go one room too far and wind up stuck in the moat, because you cannot exit the same way you likely went in.
For returning a faerie to her home plane, the Powers have granted thee a Mark. You have been granted The Mark of Abjuration! You gain 41 practices!