Be level 48 and have alot of money
It's a special armor that you can get in Cysero's shop which can do LOADS of damage. I've tried it out myself.
To acquire the "Katana" armor permutation chest-piece, you must unlock all Xbox 360 achievements, or receive 1000 Gamer Score from other achievements (Mythic Map Pack I and II, Heroic Map Pack, etc.)
there isn't any codes
He feels that to prove himself he should fight against Grendel with his bare hands.