 Cole, he was determined to let Phoebe try to bind his powers, changes his mind when he sees her vanquish a demon he declares was his brother, i.e. member of an ancient high-level demonic brotherhood. As they are clearly after the Charmed Ones, he feels their best chance is when he pretends to rejoin them, but is received by the survivors with deep mistrust, so a complex game of guessing and pretending unfolds while he finds out and sabotages their plans and the sisters doubt whether they should keep helping him or can t trust him not to turn evil again...