IIRC, Huron is (one of?) the leader(s) of the Chaos renegades/corsairs, i.e. traitor Space Marines that joined Chaos after the Heresy. That might explain why he doesn\'t occur in the Heresy novels.
Oh, and according to Wiki:
Astral Claws
The Astral Claws were created during the 35th millennium to guard against the numerous threats emerging from the Maelstrom.
The chapter was led into Chaos by their traitorous Chapter Master Lufgt Huron (thereafter known as Huron Blackheart), igniting the Badab War. They currently form a group of rebel Marines known as the Red Corsairs, who ruthlessly attack supply lines and follow Chaos Undivided. In the war they nearly succeeded in turning the Mantis Warriors to Chaos with them. Since becoming followers of Chaos, the rebel Chapter is known to habour fugitive Marines who have abandoned the Imperium and turned to Chaos, although they are very few.
In the Warhammer 40,000 background, the chapter was originally called the Tiger Claws, although Games Workshop no longer refer to this name.
Hope that helps on the mistery that is Huron
