Tenchi Muyo! War on Geminar(異世界の聖機師物語)

The story is set in an alternate world called Geminar, where countries have fought endless wars with replicas of humanoid Seikishi weapons that they found in ancient ruins. 15-year-old Kenshi Masaki, the half-brother of Tenchi Muyo! protagonist Tenchi Masaki, is summoned from another world to Geminar.