Sayl the Faithless
Sayl the Faithless was a Sorcerer of Chaos Undivided, earning his moniker through the fact that he had never sworn allegiance to any single Ruinous Power, but rather paid lip service to many, and pursued pacts and bargains with many petty Chaos godlings and daemons, betraying each in turn when expedient. Paranoid and hubristic, he was an utterly self-serving egotist and practiced murderer, whose mastery of betrayal, guile and treachery had seen him rise supreme over other rivals whose arcane powers were greater than his.
He was an ally of convenience with the Chaos Champion Tamurkhan, and as such was a Forge World creation. He wielded two magical items; the Viperous Staff, an heirloom of his Dolgan tribe in the form of a dark-iron staff entwined with enchanted snake sculptures that come alive and attack the bearer's enemies, and Schalkain's Teeth, a corpse-skin bag containing numerous sigil-etched teeth and fangs Sayl tore from the skulls of wizards he defeated, which he could use to divert the effects of miscast spells onto his luckless allies. He kept his former-fellow-apprentices-turned-single-Chaos-SpAAAUHJBHAFGHLBBLTHLAAR*FWIP* around as a pet/attack dog.
Sayl's ascendancy within the Dolgan tribe began with his swearing allegiance to the powerful Shaman-sorcerer Schalkain the Vile as one of his cabal of seven seer-apprentices, the covenant of which used their prophetic powers to guide the tribe in war and in propitiation of the Chaos gods. From the beginning, Sayl served no one but himself and worked on the inherent paranoia and suspicion of the sorcerers, and with honeyed lies turned them against each other and fanned the flames of suspicion into murderous strife.
Sayl goaded Schalkain into conducting a daemonic ritual involving Sayl and his master's three other remaining 'loyal' sorcerers, to gain vengeance on the 'traitors'. This ritual Sayl sabotaged, causing Schalkain to be torn to pieces and the other surviving apprentices to fuse together into the horrific entity known as the Nightmaw of Spawn. Although victorious, Sayl was not untouched by his treachery in the ritual, his flesh mutating and his mortal sight removed only to be replaced with hellish and maddening senses of the Daemon realm.
Hated and feared by his own people, Sayl the Faithless was nevertheless a strong war-leader whose mastery over the unholy storms of the northern Chaos Wastes and prophetic seer-craft made the Dolgan tribes under his sway greatly feared. However, as his reign stretched into scores of years, the list of Sayl's enemies, both mortal and daemon grew, and Sayl's throne was ever-threatened. When Tamurkhan's burgeoning horde crashed through the Dolgan's lands, Sayl shrewdly turned impending calamity to his advantage and allied his forces with those of the Maggot Lord. That is, for as long as it suited his purposes.