Doctor Roy Tam is a well respected Chinese physician. He is also a Chinatown contact that The Shadow can always trust.
He is more of a friend than an agent of The Shadow's, and works independent of the other agents within the crime fighter's network.
He is one of the few people to see The Shadow remove his cloak and slouch hat and reveal the face of Lamont Cranston. He knows, of course, that this is just another disguise and that Cranston is not The Shadow.