What triggers him to show up in Blackroot? I've made my way there a few times already and he hasn't shown up yet! He is down in the empty house by Liam's mother, right? Parmanian
Yes, Payne's house is the one west of Liam's mother's, and a big one it is too. The adventurer should show up after you are informed by the Panarii historian that you need to go to the Isle of Thanatos. He will gladly join you as he is always looking for adventure.