Kei is an alien - he has an external human appearance, but his organs aren't quite the same as a human's. Additionally he's outright missing one of those organs right now, which happens to be a vital organ for his species.
His abilities aren't really magic, as they're just how being an alien works for him, but I'll copy them here anyway in case they're something Leo could see (this list is incomplete, but due to that missing organ he doesn't have all his powers right now).
Superhuman toughness - he's able to leap off a cliff or out a window that's like 6 stories up and land without being harmed.
Teleportation
Projecting an image of himself in real-time, even over many light-years of distance
Shorting out technology with his mind
He's also able to rapidly switch between outfits, one of which is a nice blue-and-gray suit and the other is super goth, so it's possible that Leo would see his contrasting appearances overlapping.
And yeah I'm okay with Leo hijacking his vision.
Let me know if you have any questions. o7
Edit: I don't think his emotional connection to Belial would be visible, as there's no metaphysical connection there with Belial not in the game (aside from Belial having eaten said missing organ to absorb its powers), but if you think otherwise just let me know.
Kaltz is a devil, and that's always noticeable physically - plus his type of devil is basically an anthropomorphic representation of emotion, and Kaltz is the devil of grief.
He's also a highly magical being, so have some powers (slightly expanded at his app but this is basically it):
no subject
His abilities aren't really magic, as they're just how being an alien works for him, but I'll copy them here anyway in case they're something Leo could see (this list is incomplete, but due to that missing organ he doesn't have all his powers right now).
He's also able to rapidly switch between outfits, one of which is a nice blue-and-gray suit and the other is super goth, so it's possible that Leo would see his contrasting appearances overlapping.
And yeah I'm okay with Leo hijacking his vision.
Let me know if you have any questions. o7
Edit: I don't think his emotional connection to Belial would be visible, as there's no metaphysical connection there with Belial not in the game (aside from Belial having eaten said missing organ to absorb its powers), but if you think otherwise just let me know.
Kaltz is a devil, and that's always noticeable physically - plus his type of devil is basically an anthropomorphic representation of emotion, and Kaltz is the devil of grief.
He's also a highly magical being, so have some powers (slightly expanded at his app but this is basically it):
Leo can hijack his eyes or whatever.