Tenchi Muyo! War on Geminar S1 E9

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.