One Piece: Justice in King's Landing

Because the protagonist spoke for Garp, he was called a brag by Internet trolls. How could the protagonist bear it when he was trolled? He immediately started to troll him. As a result, he time-traveled and became the Sengoku who had just finished fighting the Golden Lion. As a time traveler, it is natural to have a system, but this system is a bit tricky, and it cannot be used normally until you retire at the age of 60.