Other than being a lesser member of the Royal Family, the early life and origin of the Inhuman known as Tusk remains unclear. His true form appears to be a worm-like creature that can create a monstrous, massive form.
Tusk was an original recruit of the Riders of the Storm, who served Apocalypse both when he attempted to reclaim his Ship from X-Factor, and later during their fight with the Inhumans on the Moon.
Although Apocalypse was revived after that incident, force out of stasis early a weakened Apocalypse lost in single combat to Stryfe. This made Stryfe the stronger master, and so the Dark Riders served him until his apparent death. Afterward, the Dark Riders carried on Apocalypse's Darwinian dogma on their own, fighting, testing, and often killing mutants who didn't meet their standards. Cyclops was their only known target who proved to be one of the strong.
Tusk was initially seen with the Dark Riders when they were adopted by Genesis, the self-appointed heir to Stryfe and Apocalypse; however, he disappeared early into Genesis' leadership and so wasn't present when Wolverine mauled and eviscerated the Dark Riders that remained. Tusk rejoined the group under its second organization under the leadership of Stryfe, but was severely crippled in a confrontation with Nate Grey.
After mutants began falling ill and dying due to the effects of the Terrigen Mist spread out into the atmosphere, the Dark Riders returned. They began murdering mutant healers, believing that their powers were a violation of the natural order, their reasoning being that mutants had had their chance at survival, and that delaying their extinction was counter to the natural order. They attracted the attention of Magneto and his X-Men, who managed to secure Triage before the Riders could get to him. While the X-Men attacked the Riders' lair in the hope of taking them out preemptively, the Riders set a trap for the X-Men and left to attack Genosha, where Magneto was protecting Triage alone. They managed to critically injure Triage, despite heavy interference from Magneto, but when the rest of the X-Men arrived to back him up, Magneto was able to overpower the Riders. He left them dead or critically injured on the island, which he then detonated and sunk into the Indian Ocean with a series of explosive charges, finishing off Tusk and the rest of the Riders.
