One Piece, My Younger Brother Kaido

When the Rocks Pirates were active, he was the overlord of the sea that defeated Rocks and was called the Black Dragon King. In the battle of the Valley of the Gods, Rocks lost to Garp and Roger, but Roger defeated the two and attacked the core of the Holy Land with one person, but was trapped in a seal due to a system error. In the year 1492 of the Hainan calendar, he woke up from the seal, met Kaido by chance, defeated him with overwhelming power, and made him his little brother. Doflamingo: Bah, bah, bah, no one can withstand his power. Be afraid and tremble, the world controlled by you Celestial Dragons will be turned upside down by him! Kaido: You say I am the strongest creature on land, sea, and air? No, no, my eldest brother, Black Dragon King Rogge, is truly the strongest creature on land, sea, and air. Barrett: Rogge, just because it's you, I'm willing to do my best, and you have to be defeated by me! Whitebeard: Although I am very reluctant to do so, I have to admit that the power Rogge possesses is unprecedented... This novel and its characters are purely fictitious. Any similarity is purely coincidental and should not be imitated.