Here is something that just got me thinking, we know that Bungie intended for 6 Fallen Lords to oppose the Light with Balor as their leader. But GURPS seems to suggest that there are only 5 Fallen Lords. Maybe the 6th Fallen Lord wasn't really how we imagined him. Perhaps he is a dark Avatara, or even Mazzarin.
I find it hard to believe that such a powerful Avatara would be long dead and transformed into a shade. I mean based on what we know of the shades, they were powerful and corrupt individuals who either joined the Dark for their own reasons or whom were resurrected for their magical abilities. It seems hard to believe that an individual who had access to such artifacts as the Total Codex and others would fall victim to the grip of death for so long, only to be made into a shade a thousand years later.
Anyway, I don't see this mysterious 6th individual as the norm for the Fallen Lords. Heck, we aren't even sure if that is him pictured in the comic.
Sincerely,
Pimpy™