Luffy, My Hardness Is Off the Charts

Travel through time and become Luffy. Awakening the Hard System. The hardness can be increased infinitely. Kaido: "This guy is so tough, he can't be hurt no matter what!~" Redhead: "His pure hardness may be unparalleled by anyone!~" Akainu: "What?! Once the giant dog went down, nothing happened!~" Auntie: "Compared to him, I'm much softer!~" Loki: "It's hard to kill with any hammer!~" Im: "Ancient weapons tickle?!" Luffy: "But the beauties are very suitable and warm. Why!~" This novel and its characters are purely fictitious. Any similarity is purely coincidental and should not be imitated.