In the early days of the multiverse, in the so-called Age Before Ages, the primordial and first demon lord called The Queen of Chaos launched a war against the forces of Divinity and Law. By brute force and threats of death and punishment, she rallied her fellow primordials into a united front. To gain cooperation from the then-servitor race the tanar’ri, the Queen took as her lover and head general Miska, the Wolf-Spider. The Queen went as far as to murder the then-Prince of Demons Obox-ob (I shit you not, this is how names were in first edition) and bestow the title to her new consort.
Under Miska’s command, the primordials and forces of Chaos were triumphant, taking over, driving back the forces of Law, which were led by the Vaati, the exarchs and angels of the Divine powers. The Lawful gods eventually fashioned an artifact to use against Miska known as the Rod of Law. On the battlefield of Pesh on the world of Eberron, the exarchs of law defeated Miska, imprisoning his now shattered form deep in the earth and shattering the Rod into seven parts, effectively bringing the war to an end.
Miska was nearly forgotten until various powers sought to reforge the rod. Servants of Avandra tortured the shattered body and psyche of Miska, attempting to goad the primordial into giving what hints he could. They ultimately failed, but reeked a great deal of damage upon the near helpless form of the giant spider. The heroes seeking to end Avandra’s power likewise found him, reaching a deal in which the he would tell the heroes where he felt the pieces to be so long as they returned to slay him with it.
The heroes ulitimately disappeared bearing three of the pieces. Nearly a thousand years after their departure, the gods and primordials sought him out as the only one possessing a significant portion of his vitality and power. They joined their meager strength to empower Miska enough to break from his prison and partially regenerate. They hoped he might pose a threat to the exarchs that had absconded with the powers of their divine and primordial benefactors. Miska has since gathered the remaining four parts of the staff.