...and fighting him and his caravan seems to be the only form of interaction.
This, and the opportunity to slaughter adventurers innocently shuffling off to Mt. Doom for some reason reminds me of an event in _King of Dragon Pass_, where strange adventurers show up at your tula.
This is, if memory serves, the only event where I've seen complete unanimity among the members of my ring -- namely, "Kill them!".
(It's worth it, by the way, if you have enough well-blessed weaponthanes, and probably a decent magic reserve -- they have a fair number of magical artifacts).