Dr. Akamashi began as a scientist under King Forland of the Forland Kingdom, tasked with researching ancient lost technology. He betrayed the king by orchestrating a coup d'état that killed the monarch, driven by his obsession to seize absolute control over the civilization's powerful relics. This act forced Princess Alita to flee the castle and ignited the story's central conflict.

A master of artificial lifeforms, Akamashi combined organic and mechanical engineering to create combat androids Ana and Yuna using recovered ancient tech. Ana excelled at aggressive close-quarters combat, while Yuna specialized in reserved long-range tactics. Despite deploying them as enforcers during the coup—where he ordered Alita captured alive for royal secrets—he developed genuine paternal love for the twins, calling them his daughters to counter his isolation.

His ambitions twisted under the influence of Cecilia, an old-world sorceress who revealed the lost technology's full potential. This corruption fueled his quest for global domination. Though he weaponized Ana and Yuna, Akamashi showed complex humanity through his affection for them, culminating in futile remorse for turning his "children" into tools of violence.

After Prince Kaito emerged as the true primary antagonist, Akamashi's influence waned. Scheming to regain power, he met his end when Kaito assassinated him with a halberd during a confrontation, eliminating him as a rival for the ultimate weapon, Teoria. His death mid-narrative positioned him as an early catalyst for later conflicts.

Akamashi's actions directly triggered the body-swap incident between Alita and Falis during the princess's escape. His legacy endured through Ana and Yuna, who allied with the protagonists after his demise. The twins ultimately sacrificed themselves alongside other lost-tech constructs to deactivate Teoria, erasing ancient technology from the world.