Just as a note, there may be some minor spoilers for RRR in this thread.
Anyway, so at the end of our session last night, we had an interesting thing happen. Rigg Gargadilly appeared in our Duchess's throne room and offered his services as Royal Assassin. Taken completely aback, she requested time to discuss the offer with the rest of the Council.
To give some background, the Duchess (my character) is NG, and the rest of our Council tends towards Good/Lawful. Also, a few sessions back, we discovered the keep where Rigg lives and killed all of the other fey living there. Rigg escaped--he gave up after the party bard hit him with a glitterdust--but slit our horses' throats on his way out. A session or two later, he killed our halfling marshal. This session, he was acting as a serial killer in our capital. Needless to say, the Council was not really in favor of employing him.
In the end, we decided to do so largely because if he's working for us, we have some measure of control over him. If he's not, he'll probably just continue killing our people, possibly including us, for fun and/or profit. His employment was contingent upon his agreeing to only kill people the Council directs him to kill, something the Council doesn't actually intend to do.
So my question now is what do we do with him? We have a Royal Assassin who we don't intend to let carry out any assassinations. Another player suggested allowing him to carry out any lawful executions we may have, and I'm in favor of letting him wreak some havoc among the trolls, since they've been doing their best to do the same to us. But if we don't let him kill people (his initial pitch included the fact that he likes to kill people), he'll likely just start up doing it anyway. How do we keep him busy and/or happy without actually letting him function as a Royal Assassin?