Mosi first appeared in Marvel Legacy #1 as a member of the Avengers 1,000,000 BC, a major player in Jason Aaron's Avengers plans with Marvel's oldest heroic mantles.
Major Story Arcs
Avengers 1,000,000 BC
Mosi was approached by Firehair for her team of champions to defend the mortals of Earth against a Celestial, named Zgreb, who was simply looking for a Celestial that landed on Earth before any of these Avengers were even born.
He would stay with the team for many battles including ones against: the first Moon Knight, a young Thanos, and an army combined of Frost Giants and Negative Zone insects. Unfortunately, during that last battle, Mosi would be stabbed in the torso and die.
After a burial, his tribe asked the Avengers to forget about them, and his team went their separate ways.
Heart-Shaped Herb: Mosi presumably ingests the heart-shaped herb like Black Panthers that would follow him, increasing his strength, speed, and endurance.
Vibranium Weapons: Mosi has weapons made of a unique metal that compliments his fighting style.