Hardened Berserker
Dragons of Tarkir — common
Creature — Human Berserker
Hardened Berserker rulings:
2015-02-25: Hardened Berserker can’t reduce the colored mana requirement of a spell you cast.
2015-02-25: If there are any additional costs to cast a spell, apply those before applying Hardened Berserker and any other cost reductions.
2015-02-25: The ability can apply to alternative costs to cast a spell.