one piece op 11 booster box A Fist of Divine Speed New and Existing Cards Can Be Combined to Build Powerful Decks A Fist of Divine Speed

If you give it first strike it can clear threats for an aggressive deck maybe, but it does run into the same issue as Steel Hellkite that it happens after blockers

Kitsa, Otterball Elite I can imagine other cards that look better in a prowess deck, but Kitsa, Otterball Elite is sneaky awesome

One mana for repeatable card advantage is absurd

One last thought

If you can find boxes in the low range (around $90), there is definitely an opportunity to make a few bucks with Theros

You can alternate between removal and card advantage while beating down with your 3/4 planeswalker, and if its not enough, you can anthem on the +1 ability for ninjas