Bella is hanging out in a Jarvis - the familiar one - handwriting a nonaggression proposal-slash-bribe. Has to be handwritten. Damn fussy demons. At least it's okay for her to conjure rather than personally harvesting the weird ink she's supposed to use.
"So, I can poke the hellgod into turning into her mortal host with a pentagon, the mortal host doesn't trust me and doesn't know much, I've got Giles looking up Glory and - relevant topics, and I'm going to check on Glory-or-Ben every few minutes so I can intercept if she's about to eat somebody else."
He disappears.
"And I will be on Mercury," she mutters. (Because where else is she going to go? Soph's bedroom? The other Jarvis?)
And she goes to Mercury. She's gotten as far as putting a nice breathable atmosphere and temperature and humidity on it, she's just been waiting till she has a look at more demon dimensions she might want to model aspects of the place after before she commits to any architecture or landscaping that would be expensive to replace. It's habitable.
Just boring.
She sits on Mercury and looks at the sky and looks in every few minutes on Ben/Glory.
"The Key is a kind of magical artifact with no fixed physical form that can be used to open a gate between worlds. Glory's home dimension is unusually difficult to access; she wants to use the Key to go home. The monks we saw were trying to keep it from her, and when she discovered them they cast a spell to hide the Key in the safest place they could think of: under the protection of that undead ex-Slayer with mysterious powers who's been making diplomatic overtures to so many demons lately."
"Because once she opens the gate, she is under no obligation to close it, and may instead choose to lead an army of demons out of it and conquer the planet."
"I agree. Not relatedly, Tony wants to know if you'd like someone to talk to about all this."
"That would be spectacular, but I'm skeptical that anyone wants to listen to me unless there is someone I know well enough to pour my heart out to but not well enough that I ever 'mentioned' having a sister." She shakes her head. "Is there a reason to want Glory not to be home that is unrelated to the gate? Like, should I not give her a lift if that seems expedient?"
"Tony wants to listen to you and has explicitly offered to do so. I suppose it's up to you whether or not you know him well enough. It's possible that if Glory goes home she might make life even more unpleasant for the demons who live there, but it's very unlikely that anyone from that dimension could leave it again without the Key."
"So that's an option if I get a nasty surprise about how difficult she is to manage at some point, I guess. I kind of expect that if I talk to anyone who likes Soph and I'm not self-censoring to the point of rendering the exercise useless they will quietly hate me."
"I don't hate you either," he adds. "But I'm not the right person for you to talk to about Soph. The situation feels very personal for me in exactly the wrong way."