You are the Thief of Blood!
Thieves are possibly the most active of the normal classes. They have the ability to steal their aspect from others and use it directly for their own benefit. Their more passive counterpart is the Rogue.
Little is known about the Blood aspect, other than at least one Blood player used his blood as a bonding point, and (through a combination of anger and empathy) tried to hold his failing team together. As such, Blood could be tied to emotion or kinship.