I really like the concept, but i think it will be better with
0 fury: pay 2 life to add 2 damage this turn (max 4 unupped |max 6 upped, or maybe 6|8, i don't know).
I think that you still have a benefit from this, and i think that it should not be pushed too much, since it's an "other" card.
Wonderful card for rushes, btw!