Mercy is a goblin baby, who Torrin is assigned to take care of. Mercy follows Torrin around most of the time, sitting in a papoose. If Torrin doesn't treat Mercy well, he is punished by Sehanine (5d10 psychic damage).
After "accidentally" killing a child, Torrin is about to have his hand cut off, when Paeris interferes. On behalf of Sehanine, Paeris offers Torrin another punishment. Instead of loosing his hand, Torrin has to live his life in the footsteps of Paeris and raise the baby from the egg (Torrin don't know it's a goblin inside) as if it was his own child.