Wearing the Legend of the Four Davas of Heaven, the "Armor of Fire" of the "Fire Deva", Musha Double Zeta and spirit retention greatly enhance their strength and posture. In order to replace the stubborn Gundam Castle that collapsed in the battle with the Dark Army, a new "Heaven and Earth Castle" was completed. However, as a mobile fortress, Heaven and Earth Castle cannot be truly completed without being ignited in the power furnace. In order to obtain a flame that will never be extinguished, Double Zeta went to Flame Mountain, where he was tested by a puppet twice his size. When the doll excellently overcame this test, it turned into the Armor of Fire, enveloping Double Zeta. After completing the ignition of the Heaven and Earth Castle, Double Zeta planned to visit the shrine that enshrines the armor of the Four Devas of Heaven. However, while traveling, he met Eisu and made him his disciple.
Kaen no Double Zeta
（Armor of Fire）（Double Zeta Gundam）Wearing the Legend of the Four Davas of Heaven, the "Armor of Fire" of the "Fire Deva", Musha Double Zeta and spirit retention greatly enhance their strength and posture. In order to replace the stubborn Gundam Castle that collapsed in the battle with the Dark Army, a new "Heaven and Earth Castle" was completed. However, as a mobile fortress, Heaven and Earth Castle cannot be truly completed without being ignited in the power furnace. In order to obtain a flame that will never be extinguished, Double Zeta went to Flame Mountain, where he was tested by a puppet twice his size. When the doll excellently overcame this test, it turned into the Armor of Fire, enveloping Double Zeta. After completing the ignition of the Heaven and Earth Castle, Double Zeta planned to visit the shrine that enshrines the armor of the Four Devas of Heaven. However, while traveling, he met Eisu and made him his disciple.