Operating as Dr. Hell's lieutenant from the flying fortress Navalon, Baron Ashura commands mechanical beasts during coordinated assaults. Tracking the demon Siren to the Himalayas after her release, Dr. Hell and Baron Ashura discover the frozen remnants of the Demon Tribe. Dr. Hell forges an alliance with their leader Zannin, employing telepathic mind control to secure the demons' cooperation against Devilman and Mazinger Z. This alliance initiates joint operations merging mechanical beasts and demons.

Baron Ashura spearheads assaults targeting the Photon Power Laboratory, including efforts to sabotage the development of Mazinger Z's Jet Scrander flight system. During one attack, demons under Dr. Hell's command—such as Siren and the tentacled Mogu—damage the Jet Scrander prototype and kidnap Shiro Kabuto and Sayaka Yumi. While Baron Ashura's forces are integral to these operations, the character remains off the frontline against the primary protagonists. The combined forces later launch a major assault on the laboratory, capturing Devilman and crucifying him on an ice cross for interrogation. After Mazinger Z gains flight capability via the repaired Jet Scrander, the ensuing battle destroys Navalon and defeats the demon-mechanical beast alliance, with Dr. Hell and Baron Ashura surviving to retreat.