Trevor has "longish brown hair" and gray eyes that are similar to Michael's.
When Trevor's parents left for Earth, they took Trevor to the Kindred to keep him safe while they were gone. They were having a second child, which wasn't allowed, so they couldn't take Trevor with them to keep it a secret that they already had a child. That was the last he saw of his parents since they died in the 1947 UFO crash.
Trevor learned about human society and social norms from the Kindred so that he could visit Earth.
When Alex uses one of the Stones of Midnight to return to Earth, Trevor follows him through the wormhole with the intent of taking the stone. On Earth, he introduces himself to Michael and later to the group. His intentions become apparent when he succeeds in taking the stone from Max, but his attempts to use it are thwarted by Kyle Valenti.