Repeated Chapter

Formless cells. Water is formless and can only maintain its shape when confined in a object or its environment. Formless cells also have the same capabilities to change shape according the will of the user. Such as creating organs, body part and even vital areas such as the heart.

The human cells have shape and its gene has structure which is claimed and rumored to be unchanging, not unless forcefully  altered by a catalyst. 

From the very beginning of his journey, David was blessed with the ability to control his body and muscles perfectly and as he grew stronger, the ability grew greater, and now he could create an extra eye out of him if he wanted although strenuously. This was already impressive as even people such as the Sun Celestial were busy training their bodies to reach such level with secret manuals and techniques.

Master Plane included. His old appearance was a result of a secret technique to obtain full fuel Formless cells.