In One Piece Odyssey Sanji’s experience and skills will be taken from him. In order to get them back, you’ll need to locate 40 cube fragments scattered around Waford Island. Below is a guide on where to find his cube fragments in Marineford. You’ll receive the Cube Collector: Sanji trophy/achievement for finding all of his cube fragments.
Marineford City Area
North Town
When leaving Gunpowder Storehouse and transitioning into North Town, follow the street south and head down a flight of stairs. At the bottom, immediately turn right. Take another right to find the cube on the side of the building.
South Town
This cube can be found in the corner northeast of the water fountain.