One Piece: Starting at the Paramount War

The protagonist is named Wang Yu, though his real name is Ibuni D. Landu. Known as the Little Strategist, he is a member of the D Clan and becomes the Fifth Emperor as soon as he sets sail.

Following the manga’s timeline, the story begins at Impel Down and branches into a new storyline connected to the Straw Hat Pirates.

Here, you can see Ace, Bon Clay, Bartholomew Kuma, and many others being rescued.

Here, you can see the protagonist beat up Momonosuke and the leader of the Tontatta Kingdom, among others, for absolutely no reason.

Here, you can make up for the regrets in your heart. The dead cannot be brought back, but the protagonist will carry on their will.