God Of Soul System

https://www.novelupdates.com/series/god-of-soul-system/

All Things of this World, Turn to Ashes, Flowing Blade-like Flame!

Crossing over to the world of pirates (the One Piece world), eleven years after Gol D. Roger's death, Roja becomes marine hero Garp's nephew and obtains the Sword Soul system, which lets him gain strength without limits and learn various skills.

Flowing Blade-like Flame (Ryūjin Jakka), Mirror Flower, Water Moon (Kyoka Suigetsu), Moon Fang Heaven-Piercer (Getsuga Tensho), Thousand Cherry Blossoms (Senbonzakura)...

Roja looked at Akainu in front of him and told him seriously

"If this sword descends, you may be roasted to death."