Twelve Demons

At the birth of the world, twelve demon ancestors came into being. They have countless lifespans and will never truly die. However, one demon betrayed everyone and began to search for and devour other demon ancestors. The other eleven demon ancestors began endless death and rebirth, but each life lived differently. Which is better, eternal life or endless reincarnation? Is eternal life more important, or friends, relatives, and lovers? And what exactly is the reason behind the betrayal of the Demon Ancestor?