There is a trick. You need many scrolls of awaken, blood supplies and the awaken spell in a somewhat high level (to not be costly). Awaken works on enemies, too. A good boss to use it on is the underprince. Just keep raising him and killing, rinse and repeat. Before the final boss, there is a Vozhd, too. That thing gives tons of experience. There is no point to it, though. Final boss is easy and the right disciplines are deadly and overpowered.