"I learned about a new form of magic, while I was here. It's called summoning; we should change the name of the Summoning Charm to minimize ambiguity. But anyway. There are three realms called daeva realms; they're known as Heaven, Hell, and Fairyland, though I'm going to fight really hard to get them known as something else in our world. Hell is populated by demons who also need a name change for Muggle relations reasons. They're people, indestructible, who can make arbitrary material objects.
- by 2100 lots of very scary stuff has been invented or discovered, and the ability to make arbitrary material objects fairly trivially permits you to destroy the world.
Heaven is populated by angels, who can change any thing into any other thing, and Fairyland of course by fairies, who can move themselves or other things with a lot of speed and precision. None of these have any stamina limits or usage limits.
Daeva can be summoned; people on worlds that have discovered this summon them under strict constraints to trade them favors. And anyone who has summoned a daeva becomes one if they die."