Acererak

Acererak is a powerful lich known and feared throughout the multiverse. Much of his past is forgotten, but ancient texts assert that he comes from a world called Oerth. Acererak travels the planes in search of artifacts. When he finds something useful or interesting, he locks it away. Although he’s powerful enough to pursue godhood as other liches have done (Vecna being a prime example), Acererak has no interest in being a god or being worshiped. He prefers to create evil gods and unleash them on mortals and immortals who oppose him.
Despite passing up opportunities for godhood, Acererak attracts his fair share of followers and worshipers. He doesn’t grant spells, nor does he give his devotees much of his precious time. Mostly he likes to watch them suffer and die as a result of their magical pursuits and folly.
Although he has lived on many worlds and crafted countless demiplanes, Acererak spends most of his time building tombs. He fills each one with treasure to attract powerful adventurers. He then kills them off in terrible fashion, using deadly traps and monsters while baiting and ridiculing them. The terror he evokes scars their souls, which he traps in his phylactery, the location of which is one of the multiverse’s greatest secrets.
Not too long ago by human standards, Acererak found an atropal adrift at the edge of the Negative Plane and built the Soulmonger to nourish it to godhood. The lich chose one of his tombs — specifically the Tomb of the Nine Gods on Toril — to serve as the atropal’s nursery.
Acererak is known to take sick pleasure in devouring the souls of adventurers, whom he lures into trap-ridden dungeons where they suffer horrible deaths. One such dungeon lies under the lost city of Omu. This dungeon is called the Tomb of the Nine Gods, for Acererak slew nine false gods and sealed them within it. More recently, he built a necromantic device called the Soulmonger, then hid it in the heart of the tomb.
Reason for this collection of souls apparently was the fact that Acererak found a way to ascend to a higher form of Lichdom previously unknown. That's why an unparalleled effort has been made to stop him by the Circle of Eight.

Early Life

Acererak was born more than a thousand years ago (in the year 219 DR) to a human woman named Kecethri and the balor Tarnhem. Acererak's mother was able to conceal her son's fiendish lineage until age ten, when a lynch mob burned down their house. Only Acererak survived due to the supernatural ability from his fiendish blood. Acererak would later cite this event as what inspired him to undertake the study of necromancy and set upon a path of revenge against the entire human race.
Acererak ended up pledging fealty to the demon prince of undeath, Orcus, and is even said to have apprenticed for some time under Vecna – possibly the only evil wizard-turned-lich (a natural career progression it would seem) more powerful than he. During his time as an influential figure in the cult of Orcus, Acererak commanded the cult’s followers to raise (or lower?) many huge, labyrinthine tombs, temples, and crypts throughout the evil parts of the world.
The Tomb of Horrors is just one.
Aside from an inhuman thirst for power and knowledge, as well as a total, psychopathic disregard for human life (which could probably be considered useful skills when you work for the demon prince of death), Acererak’s only flaw is supposedly his arrogance.
He delights in attracting powerful heroes to his dungeons with the promise of riches. He fills his dungeons with as many (vague and infuriating) clues as there are four-armed gargoyles and deadly traps.

Parents

Kecethri

Tarnhem