Mavrah had always been obsessed with uncovering the secrets of Rahi, and would never let little things like rules or personal safety stand in his way. In studying dormant Bohrok, he came up with the theory that perhaps they had evolved from being biomechanical to being mechanic shells dependent on their Krana. When the Kanohi Dragon attacked Metru Nui, Mavrah thought nothing of the danger but only of the rare specimen he could study. Eventually, Mavrah was teamed with Whenua and Onepu to study sea Rahi discovered in the Archives. After it became obvious the Rahi were too dangerous to be held in the Archives, Turaga Dume ordered the Rahi gone. Mavrah, not wanting to lose his pet project, escaped with the Rahi from Metru Nui. When the Toa Metru encountered him again shortly after the Great Cataclysm, he had become paranoid that Dume wanted him dragged back to the city. The Toa ended up sparking a feeding frenzy in their attempts to escape, and Mavrah presumably died when a tidal wave swept him away.