Firstheart are the core human. You, reader, are a Firstheart.
Bleakheart are the offspring of those humans who have grown up in regions of corrupt meta. They have mutated so that their bodies match their minds, for better or worse.
Ireheart are a breed of super-soldier meant to survive the physical and mental rigors of war.
Gearheart were made for colonization and to interface with technology. Venuan (Unplayable) are Firstheart descendants who adapted tricks like telepathy.
Undaunted (Unplayable) are the next step from Ireheart, though have a slight more Meta focus and less physical focus than them, and have a unique element which revolves around their emotions.