This page outlines Yagyū's relationship with characters in the Senran Kagura series.
Yagyū's relationship with her now deceased younger sister, Nozomi, was tight. Most of the time when Yagyū isn't busy with anything shinobi related, she would spend her time playing with Nozomi. Nozomi idolizes Yagyū due to how Yagyū is a prodigy and her older sister. However, when Nozomi died from a car accident, it devastated Yagyū greatly to the point of her putting herself in solitude since she blamed herself for not being able to protect her own younger sister from said car accident when Nozomi always looked up to her.
At some point, Yagyū realizes that she can't live in solitude forever and that memories of Nozomi could possibly disappear from her as she copes with the pain. The prevent that from happening, Yagyū took one of Nozomi's favorite ribbons and sealed her right eye so that she'll be able to remember her at all times.
Yagyū and Asuka seems to have a stable relationship. They are not seen interacting with one another by themselves but they're both considered each other friends and comrades that help out one another in battle.
Yagyū and Ikaruga seems to have a stable relationship. They are not seen interacting with one another by themselves but they're both consider each other friends and comrades that help out one another in battle.
Yagyū and Katsuragi seems to have a stable relationship. They are not seen interacting with one another by themselves but they're both considered each other friends and comrades that help out one another in battle. When it comes Katsuragi and her shenanigans, most of the time, Yagyū gets annoyed with it and threatens to kill Katsuragi to have her stop, especially if it involves Hibari. However, sometimes, she lets it slide.
Yagyū's relationship with Hibari is just as tight as her relationship with Nozomi. At the beginning before attending Hanzō Academy, Yagyū came across Hibari and noticed how similar she acts and how she looks almost identical to Nozomi. Still coping from Nozomi's death and getting out of her solitude, Yagyū decides to try again and vows to protect Hibari as if she was Nozomi. Throughout the Hanzo story mode of Burst, Yagyū took care of Hibari the same way she took care of Nozomi. At times, there were instances where Hibari was getting annoyed about it and how it makes her feel weak.
Whenever Hibari gets mad at Yagyū, Yagyū begins to go through some form a depression, but she still keeps her head up high to get Hibari to stop being mad at her. After Hibari went to Hebijo Clandestine Academy to retrieve the Super-Secret Ninja Scroll, Yagyū decides to save her solo despite her serious injury from earlier since she still feels alone due to the solitude she went through and Hibari was the only light in her darkness. However, Asuka and co. decides to go and save her when Yagyū began to feel overwhelmed by the enemy and weak due to the amount of blood she lost. At that moment, Yagyū finally realizes that she was never alone and that Hibari isn't a replacement for Nozomi. From that moment, Yagyū began to see Hibari as her closest friend but she continues to protect and take care of Hibari at all cost while sometimes giving her faith that she can do things by herself.
Homura Crimson Squad
Yagyū's relationship with Mirai is a solid one. Throughout both the Hanzo and Hebijo story mode of Burst, Yagyū didn't pay that much attention to Mirai, which angered her to know end since Mirai doesn't like being ignored at all. However, when Yagyū realizes how much Mirai wishes to protect her friends, it reminds her of how much she wishes to protect Hibari. This leads to Yagyū beginning to respect Mirai to the point where they're now good rivals.
During the events of Deep Crimson, the relationship between the two increases further to the point where not only does Yagyū sees Mirai as a good rival, she also sees her as her best friend.
Gessen Girl's Academy
It's implied that after the events of both Hanzo and Gessen story mode of Shinovi Versus, the relationship between the two is a solid one. At the start of the Hanzo story mode, Yagyū didn't care about Shiki due to the way she acts. However, she was surprised to know how powerful she was after the two fought for the first time. When Yagyū found out that Shiki is a granddaughter of Kurokage, she realizes that Shiki is fighting for his dream of a world without evil. However, Yagyū was able to tell her that she shouldn't sacrifice her whole life for Kurokage's dreams when Kurokage himself rather have her alive than to focus on a dream.
During the Gessen story mode, Yagyū's interaction with Shiki isn't that different compare to how the two interact with one another during the Hanzo story mode. Yagyū's eyepatch becomes the primary focus during their conversations. At first, Shiki just wants Yagyū's eyepatch because of how cute it is. However, after Shiki learns the truth behind the eyepatch, she apologizes to Yagyū while also explaining how she was an idiot for wanting something important and precious to Yagyū.