He had been an undead mage for a very long time, and repeatedly sought to become a demigod, to no avail. He joined in Akachi's crusade as a lieutenant in the hopes of being able to obtain several tomes stored in Eternity's End in order to reach apotheosis. The crusade was foiled, but he managed to flee Myrkul's wrath and continued to search for a means of becoming a god.
When the time for the Third Crusade was at hand, Rammaq returned to the Fugue Plane to resume what Akachi started, in hopes of trying again to obtain the Tome of Ka'Tai and the Tome of the Dolorous Sage. After the initial wave, he and his soldiers headed to Eternity's End.
The Kalach-Cha had a number of chances of foiling Rammaq's crusade, possibly even killing him. They could allow the books to be lost, and under some conditions Rammaq would see betrayal and attack. If the player retrieved one or both tomes, Rammaq sent an undead minion to assist at the Wall of the Faithless, while he left to work on apotheosis.
His fate also affected the fate of Kaelyn; if he lived, and she continued to crusade against the Wall, he would later betray her in a future crusade. This resulted in her siblings being pulled into the Abyss, leaving her a mute and broken woman.