[Well that's a question he was kind of expecting to hear, after listening to some stories around the bay in his spirit form. Just to gather information.]

Rin, Emiya and you faced Caster in her barrier. She used Rule Breaker to sever your contact with your Master and claim you as hers. That fool of a boy got badly injured and after taking care of him and the hostage Caster had taken, we left to rescue you from Caster.