Mizzarch was a Zarosian Mahjarrat slain in Gielinor's 15th Ritual of Rejuvenation, in roughly 631 of the Fourth Age.
During Zaros' reign in the Second Age, Mizzarch held the rank of Pontifex, but despite this had 'little time' for preaching, having instead been given the responsibility of overseeing civil engineering in the western half of the empire.
Mizzarch was apparently weak by the Mahjarrat race's standards and as a result was selected for sacrifice at the 15th Ritual in The North, near the ruins of the Zarosian fortress of Ghorrock. He is one of the most recent to have "faced the void," followed only by Lamistard, Ralvash, and Jhallan.
Upon escaping his imprisonment in the Jaldraocht pyramid, the Mahjarrat Azzanadra was quickly able to learn of Mizzarch's death. He did not seem overly surprised by the development, suggesting most of the race did not hold him in high regard.