Aitrus was a prominent member in the D'ni society just before it's fall. His curiosity about the surface dwellers led to his friendship with Ti'ana, whom he later married and had a child (Gehn) with. This led to his estrangement with Veovis, who later caused the Fall of D'ni. Though he survived The Fall of D'ni, he eventually contracted a deadly virus and sacrificed his life to save Ti'ana and stop A'Gaeris. He is the main protagonist of The Book of Ti'ana.