do you think Cas is pansexual?
No, but yes? It depends upon what exactly you mean.
I think Cas is pansexual, and I think Cas is demisexual, and I think the latter directly informs the former–rare, sometimes near-no, attraction, only with some type of a strong bond, dependent upon that but not upon gender. But, the latter is the more important to focus on, because it can be very, very confusing, to try to explain he’s able to be attracted to all genders, but also really, able to be attracted to practically no one, and the important part that really sets him apart is more focally his acespec (and arospec) identity.
He’d be attracted to Dean, regardless of Dean’s gender (hence why sometimes I can allow Cas/Jo, but that’s p. much it for Cas/other), because it’s Dean, either way, but he’s only attracted to Dean, and by all accounts, it seems like he’s pretty much only ever going to be attracted to Dean, only ever even interested in romance or sex in a choice-related situation when it’s Dean-related**, which is a rare and precious example of greyromantic demisexuality that I wish fandom would stop trying to screw with.
I know this confusing semantical contradiction from Cas-like experience–and even I have been attracted to more people (of any gender) with that bond than he has, he having been only ever into Dean that way, in all his millennia of existence, and seemingly unaffected by/with attraction in literally every other situation, so I generally just say he’s demisexual, and queer, and aro/ace, and when I have to specify: greypanromantic and demipansexual.
Furthermore, beyond said confusion, you’ll never catch me saying ‘yes’ to this question without caveats, because people typically treat an unqualified ‘yes’ to this question as leave to ship him with everyone, and that’s acephobic bullshit that makes demisexuals like myself feel like shit, js.
(**Were he human, and not, by his species’s nature, forced to repress all feelings, and inclined, somewhat, by brainwashing and longtime social and mental abuse, to thinking he doesn’t even generally have them, whether he should or not, he’d probably think he’s gay, straight, enbysexual, whatever applied to Dean’s gender and his exclusively, tbh–if he didn’t have access to the terminology for asexual spectrum orientations, especially demisexuality–but since he’s an angel, it clearly doesn’t feel that strange to him to be only into one person, in general, seeing as he’s “supposed” to be into no one. Not until it’s treated as strange by others, really, in which case he ends up in situations like, agreeing to things with Chastity, or retaliating against Meg’s #sexual assault ala Dean’s porno, or accepting a date with his boss, [all] because “that’s something humans do, right?”. Either way, we know he’s demipansexual, going by the narrative’s evidence, regardless of his own lack of self-awareness.)