TBH I'm not playing EK, but I asked my friend and he said that Asuras are really nice (and the best for this level) option, so if you have problem with mana - use bronze necklace, starlight vial and charm "dodge" on midnight asuras. It should solve the problem.
He also said that Venore Spectres and Dream Courts are nice, but on your level you probably won't be able to make a good exp there, you'll take up to 5 monsters on yourself and waste so much that it isn't a good idea.