Ooo IPC Caelus is a really fun idea honestly. I imagine him in this kinda AU as the IPC getting custody of him after he woke up on the Space Station. (Probably handed over by Herta) They probably see him as a walking experiment, doing research on Stellarons using him and also employing his instinctual battle skills for their own devices.

Caelus is sent on dangerous missions as a body guard/guard dog of sorts, and Aventurine felt bad for him from the moment he realized how similar their situations were. Caelus is literally collared with an ‘insurance policy’ neckband that will explode if he ever goes off the rails or the Stellaron loses control. The IPC see him as a dog to use for their own gain. Aventurine is much the same, just a pawn looking for a way out. He sees how they treat him and experiment on him, sees the lethargy after countless tests and pain hidden under golden pools by indifference. He tries to get close to him and let him know he’s not alone, because deep down, he doesn’t want to be either. Maybe one day they’ll turn the tables on their ‘captors’, together?

Caelus would take to the honest empathy like a sponge and suddenly he’s clinging to the Stoneheart and Aventurine insists he’s put on his private list of employees. It takes a lot of gambling and bribing but he manages it, just like he always does when the stakes are high. They watch each others back fully and plan in secret together.