Mithradeth is the younger brother of Baal, and originally rose through the ranks of Thymos's demons alongside him. Eventually earning the rank of arch-demon by his own actions, he was later killed by Adel in the Great War.
During the Great War Mithradeth followed his brother as usual until Baal was grievously wounded and required shelter to regenerate. He was able to extort a nearby kingdom into giving his brother sanctuary, but instead of healing Baal he used the power gained from demonic possession to put the entire nation under his command. His plot to surpass his sibling was eventually thwarted by the archangel Adel, and he was slain in battle with her.