Venetica

There are only two skills in the sixth circle, The Summoning and Final Judgement. You will receive Summoning from Benedict at the stone statue in the palace garden. Then, to get the last skill, Final Judgement, you will need to visit Amago in the Arsenal catacombs. He's a ghost, but you can't see his skeleton without The Passage skill. When you enter the catacombs, basically make a U-turn on the planks over the moat, and he'll be sitting at the desk with the red carpet underneath in a side room. Keep ploughing through the dialogue choices until he relents and agrees to train you in necromancy. He teaches other mental skills as well.