Shigure is a mysterious person and a slow talker. She is also a master of all types of weapons and believes that weaponry should be seen as an extension of the body: simply relying on the weapons strength alone will not make you a master of it. She was initially viewed as a loner, often avoiding interaction with the other residents of the dojo, besides Apachai. However, later in the series, she begins to open up to Kenichi and the others, and even partakes in certain daily rituals (e.g. dinner) with them. She teaches Kenichi how to use weapons and also got him past his fear of people using weapons against him.
It was implied by Kensei that Shigure worries about Kenichi when he is not around because she believes that he got into something dangerous, meaning she has possibly grown a liking for Kenichi. She even allows Akisame to tell Kenichi of her past, saying that it is okay simply because he's Kenichi.
Out of all the masters, Shigure trains Kenichi the least. Her actions subtly suggest that she yearns to have him as a disciple, and is disappointed with Kenichi's reluctance to use weaponry (along with his perpetual fear of her). Thus far, she has taught Kenichi mostly practical abilities, such as swimming and rope tying.
It is revealed that Shigure was raised deep in the mountains along with her father, who was an expert at both crafting and wielding weapons. On one of Akisame's travels he discovered Shigure and her father. Because her father was suffering from a terminal illness, he requested Akisame to take his life away in a duel so that he could die a warrior's death. Akisame initially refused, but eventually had to throw him off a cliff after a forced confrontation.
Before dying Shigure's father admitted he did not really want to die in battle, but was trying to be a bad example so his daughter would avoid repeating his mistakes. Akisame then gave Shigure her name (her father never gave her one) and took her to be raised by Akisame's old friend, the current master of the Kosaka-style swordsmanship. After the old man passed away, Akisame brought Shigure into Ryozanpaku. Shigure goes on missions to locate swords crafted by her father and takes them out of circulation, she keeps her exact motivations for this a secret but it is highly suggested it's because she doesn't want her father's weapons used for killing.
A mouse (who has unique abilities), later named Tochumaru, is frequently in her company. Shigure usually plays with Honoka and Apachai, and often beats Kensei for harassing her. Tochumaru is able to defeat cats (and later even armed mercenaries) with ease. It is also known for stealing food from others, which Apachai is often blamed for.
