Would anyone like to write against Castiel? I would prefer to keep it in the fandom, but I can be persuaded to give cross-overs a look. Likewise with communities; I haven't the time to devote legitimately to a game, but I may be able to make a few sacrifices if there's a really compelling premise. I don't particularly ship him with anyone, but that also means that I don't particularly not ship him with anyone either, so I'm very open to writing opposite a diverse range of characters.
At this point, I'm just looking to concoct a nice, robust plot together (as opposed to inflicting solely my visions on you), though I should note that I'm not the biggest fan of Season 7. Some themes I would like to play around with are pre-canon or early-series chronicles of either the garrison or some independent adventures (or misadventures) with another angel or a demon, perhaps set far back in the dusty pages of a history book. Call it an absurdity, but on that note, I wouldn't be opposed to dropping him in the middle of GRRM's world either. We can also go the other way and zap him forward/slantwise in time, something very much like The End or the French Mistake where he essentially winds up becoming human; or perhaps a look back to a time when he was just a clueless mid-level soldier somehow doing a time-travel routine to the middle of the Civil War/Leviathan fray. I'm certainly not limiting myself to these motifs, however! If there's anything you've been itching to play out with Castiel, by all means throw them at me and I'll give it my best shot.