X-Limit is a rare trait that is rarer than Haoshoku haki that requires a spirtit with an unbending will. The user of this technique can utilize the powers of their Devil Fruit to forcably override their bodies maximum limits. This is usually done only during extremely dire situations as the user can be killed do to stress or at the very least put into a serious coma. It was first deiscovered by Zero the White Frost during the great war with Grey Ragnarok. He was able to teach this technique to every sentinel and the secret was passes on down the generations until it was forgotten. The Sentinels were the only "race" to master this technique completely. However a select few have also unlocked this power. Two of them being Monkey D. Luffy whos gear's two and three can be considered X-Limit an