She's seemingly closest to Akisame. The two have known each other since she was little and he took her in after her fathers death and gave her the name Shigure. She is very close to him and does anything he asks her to do without question. As such, the two have developed a sorts of a father-daughter relationship.
She gets along with Sakaki most the time and share their loner and distant side of their personality. She was rather surprised when Jenny asked if they were a couple. She tends to tease him about being protective towards Kenichi's well being and calling him a "den mother".
Shigure (just as much as Miu) is one of the main target's of his perverted behavior and he has even gotten worse as the series progresses and typically responds with violence to the point of attempting to kill him without hesitation. However, she does have some, if any, respect for Kensei, but it's rarely shown.
She started playing Shogi and Go with Apachai. She and Apachai are a bad team to watch over Kencihi and Miu by the Elder, who told them not to hide themselves.
Shigure gets along well with the elder just as the other masters do and typically refers to him as elder as do the others.
She help's Miu with the dinner preperations She's quite close to Miu, often giving her advice when she needs some, even encouraging her to show how much Kenichi cares for her.
She seems to view Kenichi more than just a disciple, as noted by Miu, as she's slowly opened up more and is even fine with Akisame telling him about her past since it was him. She would even like to bathe right next to him when they were on their trip together, unconcerned with him seeing her nude and even suggests that they bathe together again. Out of all the masters, Shigure trains Kenichi the least, yet it is implied she yearns to train him, and is disappointed with Kenichi's reluctance (and fear) to use weaponry but often tries to convince him to train more. When she finds the ability to give Kenichi words of advice during her task to revive Kenichi as a martial artist, she pumps her fist triumphantly for succeeding as a teacher to Kenichi.
Tōchūmaru is her pet mouse and is considered her best friend. She is occasionally seen eating meals with him and has him follow Kenichi to make sure he's safe. He tends to be a little trouble maker and gets Apachai in trouble for eating his food, something she's fine with. When tochumaru is hurt in a fight she became's enraged and fought to save him and will not forgive anyone who hurts him. She was releaved to see he would be fine afterwards.
Hachirobe is Shigure's step-father, as Akisame asked him to look after her in honor of her father. He was also a skilled teacher towards her and taught her everything he knew. She hasn't really shown any interation towards him, but it's implied she cares a great deal for him.
Shigure's unamed father was a serious man. He also taught her about weapons and drove her to who she is today. Though he was rather strict with her, he clearly cared for her very much as his daughter and didn't want to let her see his fight with Akisame. When he died, Shigure shed tears over her fathers death, a noteworthy moment since she's never been seen crying in the series once. This shows that she loves her father very much.