Blood is Thicker than Water?

Castiel is an Omega, abused by his soon to be mate, Lucifer. He runs away and crosses into the Winchesters' territory by accident. Dean gives him a chance to prove he can be trusted enough to be a member. But soon, a betrayal leaves Castiel shaken and unsure as a new dark leader takes over his pack. Castiel must choose. Go back and suffer, or remain by Dean's side.