Bloodquest: Eye of Terror Trilogy, by Gordon Rennie and Colin MacNeil, is a collection of three works titled Bloodquest, Bloodquest: Into the Eye of Terror, and Bloodquest: The Daemon's Mark. The trilogy involves the founding Space Marines chapter, the Blood Angels, as they struggle first against the Orks and then against the armies of Chaos.
Main article: Leonatos
Captain of the Blood Angels, Leonatos was given a weapon called "Encarmine," the "Sword of Belarius," as a prize for his prowess as a warrior and for the accomplishments of his men on the battlefield. However, Garshul the Destroyer, an Ork, manages to capture the weapon, causing Leonatos to be dishonoured and then exiled. He wanders with his fellow soldiers as they try to regain their honour by hunting down the sword.
This takes them to the world of Eidolon, but they crash land on the wrong side. They are forced to battle the forces of Chaos that control the planet. They must battle against the armies of each Chaos god that control a separate continent in their path so they can finally regain their treasured weapon and their honor so they could be welcomed back once again amongst their brethren.