So far, we've always seen Onigashima primarily as the giant skull of a titanium-sized creature. It wasn't until act three of Wanokuni that we were able to go into the labyrinth of this island with Luffy and his companions. The protagonists of ONE PIECE However, you have to orientate yourself on these almost limitless meanders.
Let's start with the external structure: as mentioned above, Onigashima is surrounded by a huge skull that acts as a dome. The inside of it The skull is big enough to fit giants like oars and also a part of Kaido in the shape of a dragon. Of course there is also a whole city with different parts of the city and a central square and a tower. As disclosed in ONE PIECE 993, this is The tower is five stories high and two underground, each of them divided into two levels. And these floors seem that high indeed.
To get to the dome where he has to face Kaido, Luffy has to go five floors up at least for the moment in the company of Sanji and Jinbe. Undoubtedly, the higher they go, the stronger the opponents will be, and therefore it is possible that Luffy could reach the top alone while Sanji and Jinbe stop to face King and Queen.
After the fifth floor, another staircase leads to the top of the dome, which then serves as the sixth floor and where Kaido and the red sheaths face each other. It will be some time before Luffy reaches the top to take down the saga's toughest enemy.