"It is not that Krii cannot die, rather, their bodies do not accrue damage through the mere passage of time." This "functional immortality" is the result of several cooperative evolutionary factors working in tandem with deliberate bio-tech enhancements implemented over the millennia. Firstly: their bodies do not produce scar tissue naturally and can regenerate any tissue type; entire limbs, organ systems, teeth, even brain and nerve tissue can heal completely without lingering complications or pain. Secondly: all Krii possess within their cellular matrices a hereditary endosymbiont which has been transmitted from mother to child for millennia, a bacterium which -in exchange for room & board- grants Korrinthian cells access to its Crispr Cas9 organelle. A naturally occurring gene editing system designed to repair and maintain the amino-acid chains and maximize the health and lifespan of its host cell. This system dramatically slowed down the aging process of an already venerable species, as well as eliminating cancer, viruses, and genetic diseases all together. However; it also eliminated their species’ ability to evolve naturally, a process which is now controlled by machines; and it was through these mechanical enhancements that the Krii were able to perfect said system and initiate a state of perpetual regeneration.