Early in its life, the ilpdor lived in the lake near the village of Crellum. However, male Stoics from Janjur Qom's capital city reduced the population of fish—the main source of food for an ilpdor—in the lake through overfishing. Burenn came across the ilpdor when it was starving due to the lack of fish; the ilpdor did not eat her on sight only because of its smaller size. She fed the ilpdor the meat and cheese of a garfren and bonded with it, and she soon named it Erb. The "partnership" formed between Erb and Burenn allowed her to catch more fish by training the ilpdor to drive the remaining fish from the lake into nets. The female San'Shyuum of Crellum provided Erb with food, while the ilpdor scared away hostile raiders or threats to the village.
In 850 BCE, Burenn and her sister Lilumna received a message from the San'Shyuum of High Charity that invited them to live a life of luxury on the holy city. The two sisters and seven other females accepted the offer, and Burenn made arrangements for her mother to take care of Erb in her absence. The nine females met with San'Shyuum and Sangheili from High Charity at the lake outside of Crellum, with the females riding aboard of Erb. The group traveled to the Covenant dropship nearby, but were intercepted by a unit of Stoic warriors. As a firefight broke out, the Prophet of Inner Conviction ordered the females to take cover behind Erb. However, Burenn mounted Erb alone and charged at the Stoics. Using its powerful jaws and sharp front claws, Erb destroyed the folasteed mounts and killed several Stoics by breaking their necks. The last surviving Stoic fired at Erb's neck with his weapon. Mortally wounded, Erb charged at the Stoic and stopped in its tracks just as the animal bit off the warrior's head. Spitting out the Stoic's head, Erb collapsed just as Burenn jumped off in time to avoid being crushed. Burenn mourned Erb, and she was later thanked by Inner Conviction for bringing Erb into the battle.
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