Summoning is a spirit magic. Necromancy is very common in Thanatos. As far as limitations go, there really isn't a defined set of limitations. You set your own caps, so it can be really easy to make an Overpowered character, but you will find that OP characters can be really hard to write engagingly. Trust me, I have more than a few "dead" characters because they are so op that they just aren't interesting.
Hope this helps!
