The Fourth

The 4th eldest brother of the great 10, his scientific field of expertise was mutation. The 4th sought to improve all fauna through mutation, and the fruits of his labor are evident in the world.

The Awakening
The 4th's Awakening is a microscopic virus capable of rapidly altering fauna DNA. Most of the fauna are resistant to this virus. The few that aren't undergo what has been dubbed "The Awakening", which is a fauna's rise to sentience. These fully sentient species are fully capable of speech and free will. Some species tend to exhibit extraordinary abilities which can be either mental or physical.