You know those moments in life where you look at someone and just sort of know they complete you? Where you try to picture where you'd be without them and you can't, but you do know that you're a better person, just because they're there? You know those moments where you look at someone and know you can never let them go?
Balthazar isn't having one of those moments. He's sick of trying to get things done without a vessel, though, so he's gone and pegged Kelly McCoy as "the one" anyway.
He wants someone people won't look too hard for when they disappear, and he'd like someone easy to get on with. Of course there's no rule that says an angel and his vessel need to "get on" at all. If you're not in the mood to deal with their whiny little voice in your head then it's remarkably simple to shut the poor sod out completely, once you're in. All it takes is a moment of concentration and they'll fade away, easy as putting on headphones to drown out other commuters on the train.
Balthazar doesn't want to do that, though. Faking his death was too much trouble to do again, so he intends to keep the charade going as long as he can. That means he won't be going home any time soon, or otherwise crossing paths with any of his "brothers" or "sisters." He figures it'll be nice to have someone around to talk to.
Kelly's recently unemployed, single, with no friends or any local family. He spends his days sitting around his flat, binge-watching mediocre American dramas and masturbating to Japanese porn.
"Not to judge," he tells Kelly, having popped into his head to explain the whole vessel thing after interrupting a particularly cruel nightmare, "But you seem to be at what they call a 'low point' right now." In the nightmare Kelly's wifi had kept turning itself off just before he hit the point of no return. Luckily he seems to have lost interest in that by this point. Funny how announcing you're an Angel of The Lord is such a boner-killer for some humans.
"You're supposed to be an 'angel' and got nothing better to do than spy on some tosser that wanks five times a day and never leaves his flat." Kelly cocks an eyebrow and smirks. "I suppose that'd make you the expert on 'low points.'"
Oh yes. Oh Dad yes. Kelly's definitely the one.
"Fair enough," Balthazar says, "That's the thing about being an angel, though. Hard to get much done without a vessel. Can't hardly talk to humans, can't hang about anywhere that hasn't been consecrated, can't have sex…"
"That's allowed?"
"You won't see anyone stopping me, I can promise you that."
"So… if I said yes, what would I be doing while you did all this stuff, then? Watching?"
"Sort of, but also sort of experiencing, you know? It'd still be your body, after all. So what do you say?"
"I dunno…"
"Tell you what: Say yes now, we'll do one day, and at the end if you decide you want out, I'll put you right back in your flat, leave, and never watch you wank again. Deal?"
That's a lie. There's no changing your mind once you've said yes to an angel. Much as Balthazar would prefer something amicable, he knows he doesn't have the patience to start the vessel hunt back at square one if Kelly decides this isn't his cup of tea.
Luckily Kelly takes the bait, and Balthazar spends their first day shagging supermodels two at a time and taking occasional cocaine breaks in between. By the end of the trial period Kelly's a hundred percent on board.
Before long Balthazar's overjoyed to discover that Kelly's a big fan of people-watching and keeps a delightfully bitchy running commentary on everyone they see.
Look at that one, he hears when his eyes skim over some random girl on a sidewalk, Must've bought that dress about five thousand Jaffa Cakes ago, bless her.
What's he hiding under there? This about a man who's selling Balthazar his soul and happens to be sporting an impressively awful combover. Bet if you tried to look under it, it'd sort of peel back and roll up like a price sticker, you know? Once Balthazar conjures the mental image it's all he can do to keep a straight face, and he can feel Kelly's satisfaction at nearly getting him to crack. That's an odd thing about leaving the line open like this: Every so often Balthazar will catch a layered wave of secondhand emotion from his meatsuit, like sexual ecstasy colored by a hint of awkwardness when they're shagging someone, or condescension plus a shade of boredom when he's doing his heckler bit.
That bloke's bloody scary, is Kelly's initial assessment of Castiel, He's like one of those Americans on the news that brings a machine gun to the office one day 'cause the lady at the front desk won't toss him a pity shag.
What, Cas? Balthazar snorts. Never.
That's what they always say on the news, though, innit? "Him? He'd never—except he did, didn't he? And come to think of it he always was a little off…" That's what your mate is. Off, like.
He's wound a bit tight, sure, but he's not going to go full barmy on us. I know Cas, okay? We go way back. Best mates, him and me, so don't you worry about him.
The last thing Balthazar experiences—barely registering beneath the pain of getting literally stabbed in the back by his best mate—is the frankly insufferable way Kelly's mortal terror is tinged with a note of smugness.