Mazi was an inhabitant of Ureh, living in a monestary that had been carved into Mount Nymyr before the city was built. He collected a wide variety of plant and animal specimens, which he stored in his abode. He was a good friend of the city's ruler, Juris Khan. As the city became besieged by Diablo, he contributed the most to the spell that would supposedly take the city into Heaven. However, he discovered Khan's affiliation with Diablo, and realized that the spell would in reality drag Ureh into Hell. He reconfigured the spell, which saved Ureh from descending into Hell, but nonetheless left it stranded between worlds. He was teleported outside the city by Khan, and watched as Ureh faded away before his eyes. Mazi was left a broken man, and was found by the Priests of Rathma. They cared for him until his mind had healed enough, but afterwards, he left them, determined as he was to join his family and friends in Ureh. He traveled the world, looking for a means of joining his city. Along the way, he made notes of his discoveries. But twelve years after Ureh's disappearance, he returned to his now abandoned homeland, in the company of Humbart Wessel and other mercenaries. Humbart observed that Mazi blamed himself for Ureh's fall, and often saw him praying for redemption. After seven days, Mazi again approached the edge of the city's ruins. Wessel opinioned that they should leave, but Mazi refused. As the light shone on Mount Nymyr at just the right angle. Ureh appeared to shimmer before their eyes, and Mazi entered. He never returned to them.
Upon entering Ureh, Mazi discovered Father Tobio, who had been imprisoned by Khan. Khan sought to return Ureh to the mortal realm, and they sought to prevent this, by destroying or removing the Key of Light and the Key of Shadow. Khan caught him with the Key of Shadow, and after a furious battle, defeated him, carving him into a sentinel. However, Tobio had managed to escape with the Key of Light, so for now, Khan's plans had been thwarted.
The writings of Mazi and Wessel were recovered by the Vizjerei Sorcerer Quov Tsin, who followed in Mazi's footsteps, trying to gain access to Ureh. Khan and his daughter Atanna presented a false version of history to the company, claiming that it was Mazi who had tried to damn them to Hell. In truth, Mazi had confronted Khan, and Mazi was embedded into Mount Nymyr itself. His body was left immobile, but his mind was still allowed to function. His body was found in the rock by the Necromancer Zayl and the mercenary Kentril Dumon, as they investigated the lower levels of Ureh's palace. Zayl suggested that Mazi was no longer concious, that his mind had been lost due to the extended period of imprisonment. However, he was indeed still concious, causing Zayl to perform a mercy killing. Mazi looked at Zayl with something that looked like gratitude, before his eyes closed.