(Edited from original source to better fit RPs setting.)
Phyrexians, are an immortal species of this world.
A form of bio-mechanical life that due to their determination to replace flawed flesh with more efficient mechanical parts sit in a strange state of unlife.
They do not die of age, but CAN be killed if one tries hard enough.
Phyrexians come in all shapes and sizes depending on an individuals age, purpose, and level of respect among their community.
They all start out humanoid, with some differences and eventually are remade with new mechanical parts to fit whatever purpose or goal they are created for. More often than not they are so heavily changed and modified they no longer really look human, and end up looking more monstrous.
Most do not need to eat, though the ones that do are carnivorous. Many do not need to sleep.
What classes are commonly found amongst this race?