I'm making a faction that will largely depend on the Vacare so if I may offer some things I'd like to see:
- A form of mind control. Obviously, I expect the Empire to have several countermeasures in place so Vacare can't just mind control whoever they want. But it could make for interesting situations.
- A form of mind reading. Which again, has several counters but it would feel obvious, no?
- A form of void-energy control. My idea would be that they can open small, temporary portals that allow the 'matter' of the void to slip into reality, take the form of some dark-energy substance and be shot off. The portals could also serve to act as a mini, very local, not that powerful singularity.
- Divination. I wanted to say precognition but with Divination, we can add some ranting of space gods. (because who doesn't love slightly unhinged sorcerers?)

I'll probably come up with several more ideas but these are the ones I'd very much like.