[It's true that between Gabriel and Michael, any conversation with the other angels could go rather badly for Adam. As things stand, though, Castiel has no idea that Adam already know what he is, and he doesn't trust the boy enough to say it outright.

Castiel takes in Adam's words, shock passing over his face a few times. This boy had been destined to destroy the world, just as Sam and Dean had been tools in that same machine?

He'd been meant to lead the Horsemen, even. Castiel is particularly surprised at the mention of Metatron, seeing how he'd been making his own trouble back home.]

Then you were supposed to have been groomed or... conditioned to want to destroy everything? Are you a demon? Or an angel? [He might as well get to the core of this now.]