I have a few books to recommend to you. The first was One Piece: Tricking Luffy into joining the Army, Changing the Plot to Become Stronger. The protagonist had the Rebellious System that could change the plot to become stronger. There was also " The Cultivation Journey of One Piece World ". The main character could cultivate all kinds of demonic fruits and domineering abilities to increase his strength. There was also " Taotie: Devouring and Evolving from the Destruction of the Pillar." The main character had the Taotie bloodline and could devour all kinds of items to strengthen himself. I hope you like my recommendation.๐