Awakening drains it like no other. When you start one shotting mobs, you don't require side dodging, which recovers mana. There are no awakening skills or any actual viable skills that recovery mana back quickly. Awakening standard attack is the slowest @#$%ing clunky @#$ @#$% thing ever and it doesn't even give much mana back. They gave DK the same large pool of mana like witch/wiz, but gave it zero of the mana recovery those two get. Other classes have fairly small resource pools and can recover them with one tap of an attack. That's just the mana, health sustain is BS too less you're able to kill everything instantly before they touch you. Class is horribly newb unfriendly.