Castiel looked down at his hands, which had stilled at this point, deciding how he wanted to explain. There was a lot, with Naomi, and so much of it Castiel didn't know himself. Signing, also, limited a bit how much he could say easily, and finally he decided on a very condensed version.

There was an angel in Heaven that few knew of. Her job was to force obedience to orders, and she could modify memories and parts of an angel's personality to do so, and she can directly control them this way as well. I don't remember more than what she did most recently, but I have apparently been rebelling for a long time. Entire pieces of memory are missing, and there are fakes ones in their place.