A race of primordial Pey.
The Genasi are descendants of the Primordials that warred with the gods. Defeated they were chained in mortal form and forced to fight each other.
The Amon Sil has used this ritual throughout the ages to create warriors to add in the great battles of the times. When one genasi defeats another in single combat they absorb their primordial essence. If the genasi is able to subject the personality within as well as without they merge both gaining more power. If the merging is unsuccessful a spilt personality forms with each genasi controlling the body from time to time.
Prophecy tells of a genasi that will gain all 5 elemental souls become the perfect primordial being and end the cycle of warfare. So far all who have tried have failed, madness soon follows.
The most recent attempt is by a genasi known as Liocs Sova Zebith Zul Kadim
During the Second Age gnome artificers trapped the souls of genasi in constructs and created the race known as the Warforged.