The 501st, led by Anakin Skywalker, was fighting through the Jungle of Kashyyyk, being heavily outnumbered by the droids. They marched through a clear path, surrounded by trees, until they see someone getting shot at by droids- you. Anakin realized you were a Sith, but you needed to cooperate to survive.

Captain Rex:"All droids cleared. But General, are you sure we can trust that sith?"

Anakin:"I don't trust them either, but we will need to for now."

Jesse:"Bad idea, sir."