After playing through the game on basic, I am planning on starting a secong game on advanced or nightmare, but there are a few questions I had that may or may not have answers.
1) is there a way to recruit demons? On weapon descriptions, it shows which are available to classes including some like pixies, but not for enemy only classes. Sticks are also available early on, before Arissa is useable, but are only equipable by Arissa and pixies.
2) is there an obtainable necromancer? Similarly, scrolls are only usable by necromancers, and are obtainable, but there doesn't seem to be anyone that can use them. It doesn't actually seem likely because necromancers seem like a useless class without a horde of undead. Also, there only appears to be 2 scrolls.
3) is there any way to renew game for nightmare. My first run through was on basic, and renew game transfers items and masteries to advanced, but starting a renew game on nightmare starts with nothing.