After Cain killed his worthless brother Abel, he was unjustly cursed by God to wander the earth forever. On his travels, he met a sympathetic woman named Lilith. They discovered that they had a mutual beef with their creator. Lilith, first wife of Adam, refused to suit to her husband and was cast out of the garden by God. Cain, Adam's first born son, was rejected by his father after his precious sacrifice wasn't accepted by God. The two kindred spirits founded their own race of humans called Evangelions, and set about to bring their former benefactors to their knees.

This race of humans is stronger and faster, growing to be about 8ft tall. Otherwise, they are biologically similar to regular humans. The biggest difference is that they possess a unique organ referred to as a "core". This organ allows for the regeneration of cells, giving Evas the ability to regrow body parts. Arms, legs, and even the brain can be regenerated almost immediately, providing them with a form of biological immortality.

However, this core has a weakness. Although it can regenerate cells and other organs, it is unable to regenerate itself. It cannot repair damage done to it, which reduces the Evas regenerative ability. Once it has taken too much damage, the being dies for good.

How would an organ that regenerated cells be unable to repair itself?