The Fourth Elysian War, fought between Elysian Celestial Empire and Yamatai, began in YE 23 and lasted until YE 25. The Elysian Celestial Navy made a serious attempt to retake Yamatai while the quickly-growing Star Army of Yamatai was still small.

The war ultimately resulted in the destruction of the Yamataian capital city, Geshrinopolis, in YE 24, the glassing of Damasica (Neo Kohana), and the death of national hero Ketsurui Chiharu during the Battle of Ralfaris in YE 25.

After Ketsurui Chiharu's death over Ralfaris , Ketsurui Yui used the Patrician, Kiriel Zemerias's love for Chiharu and the fortuitous resemblance of Shoki to Ketsurui Chiharu, to negotiate a peace treaty between the Elysia and Yamatai with Shoki posing as Ketsurui Chiharu.

The Star Army has a Fourth Elysian War Service Ribbon.

• Ishida Jon
• Ketsurui Chiharu
• Tomoyo