Col. Heidern is the captain of the flagship Domelus III and one of Domel's trusted friend and staff officer. During the battle at the outskirt of the galaxy against the Comet Empire's ship, Heidern assisted Domel is driving the ships of the Comet Empire back and berated Berger for having a big head. When gathering soldiers for the upcoming battle at the Rainbow Cluster, Heidern met some of his old war friends which gave Domel some confident in the battle after seeing most of the soldiers were young boys and old men.