The Sar'den have no lungs, instead they breath via miniscule chambers that lie just under the surface of their tentacle skin. They also have no real heart. Their purple blood is spread through their body through small muscular tubes that act as a heart. These tubes surround the entire inside of the Sar'den skin as they draw their oxygen from the tentacles. A Sar'den also has no digestive organs.
Food is processed by sucking it through a small opening in the end of a tentacle.
After a short trip through the tentacle the food is broken down into sugars and residue's are ejected again via the breathing chambers. These sugars then feed the Sar'den. Mostly their well developed brains that lie exactly in the centre of their spherical bodies. All adult Sar'den also have the power to change their appearance. If an adult Sar'den is troubled, his skin colour will change from blueish-purple to deep green.