Mom & Dad(Unknown)
Ichika Orimura(Younger Brother)
She was the Japanese pilot for the first-generation IS machines and was said to be the strongest IS pilot at one point before retiring.she looked after her brother Ichika and raised him by herself after their parents abandoned them at a young age.Chifuyu was also the one who enrolled Ichika to the IS Academy to keep him safe from other countries. Chifuyu once wielded Yukihira, a powerful IS energy blade now in Ichika's possession. Chifuyu was a close friend of Tabane Shinonono.which explains how their younger siblings became childhood friends. Tabane also implies (heavily) that Chifuyu piloted the "White Knight" an IS that protected Japan from a missile attack 10 years prior to the series.