The final chaos lord is more of a lord of chaos undivided. Although he won't be a part of the Lords of the Black Crusade apocalypse unit, he could readily form an icon bearer in a unit of counts-as bike. The simple premise for this model was to have an icon bearer on top of a daemonic steed / bike armed with some w40k weaponry. In this case, it is a spare twin-linked bolter from the chaos space marines set. There really is not too many other conversion works taking place here: nice and simple does the trick.