Jindai Chihaya

Chihaya is a foreign existence in sengoku period and that caused her to death unless she is recognized as not exist in sengoku period. The real chihaya have been dead 3 years ago because heavy ill and current chihaya is kohaku that do time travel after touch imperial sphere carelessly (yuika route and kohaku route) and then spend 3 years in sengoku period as "jindai chihaya". Her memories as kohaku is locked when time traveled and unlocked after receive huge shock or brought back to the original timeline.