"Course not, they're part of me. I can change 'em the same way I could with my deck, see?" He inverts the black and white parts of the colour scheme with a shimmer of rainbow mana.
He giggles, puts his hand on the table, deploys a magical diagram, and lifts his hand away from it. The centre of the diagram fountains tiny glowing spheres in a dazzling rainbow of colours; they rise into the air in a streaming column and then drift away like soap bubbles, slowly fading as they go.
"It's easy enough for me. I don't know how easy it'd be for somebody who wasn't a Device."
"I dunno. I don't even know if I can come back when the spell that's holding me here breaks. I think I can, but it's hard to be sure."
"I mean come back by myself. Using my dimensional transfer magic. So I don't have to keep getting somebody new to summon me every time the last one dies."
"Yeah. I can self-repair; as long as I'm not wasting huge amounts of mana on other stuff, I'm not gonna run out of blood."