Khet

A body is a physical man made object that can be used as a vessel for a soul thanks to Crystals.
It can be made from range of different materials and in many different forms and shapes depending on the region or the purpure of the body. For example in a swampy environments, the bodies are made to suit this terrain more with frog-like toes with webbing so they can walk on mud better.

Upon entering a body for the first time, the soul need to learn how to use it properly first, especially when its a completely different type of body, or its made out of different materials.