One beggar boy in Limòri catches Sadima's attention:
He had a cheerful demeanor, and a terrible scar. Someone had tried to cut his throat, the knife sliding up behind one ear as he fought for his life. (39.1)
He's a clever kid, too, playing along with Sadima as she pretends to ignore him while actually slipping him some money. The reason for pretending not to get money is that the bigger kids would beat him up and take it if they knew.
Later Sadima discovers him caged in the tunnels that Somiss has Franklin doing something in (59.16). Clearly Somiss is up to something, and the beggar boys are serving as his guinea pigs.
In Hahp's timeline, he meets a wizard named Jux who's most likely the grown-up version of the beggar boy: "I had never seen him before, I was sure—I would have remembered his scar. The wide purple-pink line ran across his throat at an uneven slant, then upward to disappear behind his right ear" (52.8). He takes Hahp to his new tasks after Hahp has made soap and been rewarded with a green robe.
Jux has a kinda strange sense of humor. When he gives Hahp the task of turning a stream of ants away from a glob of honey, he grins and says, "If you can't… you will be starved. Or hanged… Probably starved" (56.5). Er, thanks? LOL starvation?