Easiest way to make someone much stronger is that they made a deal with an occult power. Strength in exchange for something else.
However, a better enemy would be someone who is equal to them but makes the best out of situations. Manipulative being the best example. He has somehow convinced 16 others to join him and therefore he must have some hold on them through various reasons.
Spell names I'm a bit useless on but try bashing the keyboard and seeing what words you come out with. Some on them may end up like spell names
