Ben

Ben was first introduced in The Maze Runner, as he was going through The Changing, when Thomas walked in on it. During The Changing, he regained memories of Thomas, and according to Ben, it was enough to make him want Thomas dead.

After recovering from The Changing, Ben goes insane and attempts to murder Thomas after he wandered off into the Deadheads. Despite Ben repeatedly stating that Thomas is evil, Alby tells him to stand down, but Ben disobeys, and makes one more attempt to murder Thomas, this time with a knife. Alby prevented the murder by shooting him with a bow. The arrow lands in his cheek, and Thomas assumes that the boy was dead. This is later proved to be false, as Chuck later tells Thomas that the arrow missed Ben's brain, and he has been healed by the Med-jacks. Ben begs for mercy and blames it on The Changing, which apparently was still controlling him. He was most likely killed anyway, as shortly afterwards, Ben is banished to the Maze, with the use of a metal pole with a rope that was tied around his neck collar, where the Grievers most likely killed him, though it's never mentioned what happened to him.