Both. [ the answer is a calm report, explained matter-of-factly as Cas finds his place on the couch, watching how Sam settles and doing his best to mirror it exactly - monkey see, monkey do. ] This body’s a vessel, my true being is a multidimensional consciousness composed of light waves and energy.

[ Sam’s briefing is thorough, something Cas appreciates greatly, and he listens attentively through the whole of it, frowning progressively deeper. No memories, no name, nothing to define himself by, simply the core of his being. And what is that? Perhaps what he’d first been programmed to be, with everything he’s seen, learned, felt at the Winchesters’ side washed away. Tension creeps up his spine, dragging anxiety behind it, fear of what might show up in the Horizon for Sam to contend with. ]

I certainly hope not. [ less for his own sake, more that a human shouldn’t be exposed to the level of horror and violence he’s witnessed (and committed) in the long span of his life. Not forgetting the trauma of Sam’s torture in Hell he’d shouldered for him. His throat bobs, swallowing thickly. ] If I have no memory, I assume I’ll forget my secrets as well.

[ sounds liberating, in that sense, but it doesn’t edge away the apprehension of what his core self may truly be. Cas doesn't dwell on it long. ]

Will my mind notice if my body’s tampered with while I’m in the Horizon?