200 years ago the scholar Linnaeus sorted all animals into five classes: Mammals, Birds, Reptiles, Fish, Amphibians. But in reality there was a sixth class: Kongou.
It is uncertain when, where or how they where created. While their physical appearance is similar to mammals, they are a completely separate lifeform.
Since 4.6 billion years ago when the Earth was born, living things have lived inside the food chain and a changing environment, and in order to deal with the outside world, their forms continually succumbed to the compromise known as evolution. However, the Kongou remained at the top of the food chain, and refused to adapt to environmental changes. Their cells have reached perfection.