This is a one-shot for level 10? You're going to be playing Tomb of Horrors, so plan accordingly.
Thanks for all the suggestions. I really want to try something I wouldn't normally play - that is a tank or sneak.
...
I'm thinking a hobgoblin wizard. I'd like to go necromancy, but I can't make him so unlikable no one will want to travel with him. I'll have to look over warlock again too.

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.