Nothing he could offer would tempt me. I hate slavery and slavers. My usual favorite line is 'leaving him to the mercy of the elves'. I wipe out the whole stinking lot of them, even knowing I can sneak in the back way and leave the ones in front alone, I deliberately provoke a confrontation and kill them all.
Maybe my Aeducan might have, but by the time I got to that point of the game, I just wanted that run done (hated the origin). So i did a lot of console command killallhostiles that playthrough.
Since my preferred warden is a Surana, you do the math. Technically none of the elves are her family, but they are elves, and she does feel kinship with them since they are her own kind, and this guy is about as evil as they come, and can still lay claim to 'human'.
No pleasure he offers could compare to the joy I take cutting him down.