Tam Song is a powerful Shade who can control shadowflux. He is first mentioned in Book 4: Neverseen. He has a twin sister named Linh who is a powerful hydrokenitic. In book 4 we meet him in Exilium and he acts like a caring (and overprotective) brother of Linh. He and Keefe do not get along they help Sophie flood Ravagog.
In book 5 he shows his powerful abilities as a shade and finds the secret behind the Lodestar mirror.