i'd like to humbly make some suggestions for your consideration:
1. give demon possessed characters a second choice. rather than just allowing them to get an exorcism how about letting them do a quest of some sort for the demon which rewards them with an upgraded terror mask? such an option opens up another interesting rp choice for those of us that do that sort of thing: a character that willing chooses to remain bound to the demon.
a. another thing with the terror mask, make it so when you're captured it can't be stolen from you. while trying to become a ghost i found that enemy parties steal that mask 90% of the time. if not that, at least give us a chance to win it back from the party that stole it. it's not like you voluntarily took it off, so croaking when you attempt to win it back is not nice, lol.
2. make manitcore's head either thinner or smaller all around. it's a little difficult as a lancer to hit anything when the tip of your lance is in his head making it impossible to see it.
3. now that there are level requirements for necromancy ranks, remove that necessity to make each of those recipies to make the next rank like it used to be. honestly, i like the idea of needing a certain level to get the next rank much better than having to make each of those recipies in the necronomicon. i mean, the ai necro parties are specialists, why can't we choose to rp a speciliast necro as well?
4. consider using one of the chests in the nightmare realm to bring forth a nightmare themed mount, armor/weapon set, or unit/hero. have the required item be x number of the nightmare cube itself. i understand why you made the nightmare cube self spawning like that, but one would think that whatever entity created the cube wouldn't have made it do so without more of a reason than just annoying who ever owned it... well, unless of course Loki created it; that one's sense of humor might very well have thought it a grand joke.
5. to expand the after level 30 game play you could give anti-heroes more choices. such as when zeus congratulates the player upon reaching anti-hero status, have him send the player to either of his older brothers. as more of a good aligned anti-hero, the character could go to poseidon and become his champion like the character creation choice. as a more traditional anti-hero, using the darkness to combat the darkness, the character could go to hades and become his dark champion. some of the rewards a character serving hades could get are the items they would get otherwise by serving the blood fountain and fighting him, becoming a lich or adding in a choice to become a death knight. have always been partial to death knights as far as undead went, and i've been waiting for that option to appear in game since we got the option to become a lich.
a. another reward for this choice could be whichever god the character chooses to serve teaching them how to upgrade hired blades/merc cavalry into an appropriate elite unit: templar/crusader type units for poseidon, dark knight/champion for hades.