Chifuyu Orimura  

Brunhilde, Chi, 織斑千冬

Chifuyu is Ichika's older sister who is currently 24 years old and serves as his teacher at the IS academy. She has a deep affection for him as she considers him her only family after their parents abandoned them. During her career, she was known to be one of the strongest Japanese pilots for the first generation IS machines before retiring. After retirement, Chifuyu took care of Ichika and raised him on her own. She enrolled him in the IS academy to ensure his safety from other countries. Chifuyu previously wielded Yukihira, an incredibly powerful IS energy blade that is now under Ichikas possession. Her close friendship with Tabane Shinonono, the creator of the IS, explains how their younger siblings became childhood friends.