Iroha is a flashy and beautiful high school girl with light pink wavy hair and light or dark brown eyes. She has many outfits she wears at times, but at school she wears her school uniform consisting of a skirt, shirt, and bow.
Iroha is a very honest girl who is a little bit shy, but not all that much. She is also quite easy-going and can get jealous rather easily. Iroha doesn't like it when others say rude things about her friends.
Iroha is always been looked at as your typical "bitchy" girl, and a person that steals boyfriends, she's always wanted a boyfriend that would listen to what she had to say, a boyfriend that wanted to be with her because of who she was, not because of her so called "pretty face".
She seems to play boys, as you can see quite early on in both anime and manga that she was with two boys. Iroha fell in love after a little bit with Hikari Tsutsui she seems to have fell quite hard, she always wants to be with him, and gets quite jealous. She has been suffering from the main common lung disease asthma that's why shes very calm in a way.
A girl with a less-than-stellar reputation as "the girl who sleeps around", Iroha is actually quite the contrary. She is not as promiscuous as many think her to be, although she actually does not have female friends (due to her reputation). She is, however, a good judge of character and sought to make Hikari Tsutsui her boyfriend after seeing the good in him, despite his reputation for being a "creepy otaku" who is universally rejected.
Tsutsui, also nicknamed by Iroha as "Tsutsun", is Iroha's boyfriend. Tsutsui living a primarily isolated life in rejection as an otaku, meets Iroha's initial kindness with skepticism and even conceit, as he first sees her as "everything he hates in 3D girls". However, Tsutsui finds himself helping and defending Iroha several times when she finds herself in a difficult situation due to her less-than-friendly disposition, and begins to harbor feelings for him after he defends her against her abusive ex-boyfriend.
It seems that Iroha sees nothing but the good in Tsutsui, and although his insecurities can be difficult for her at times, her love and faith in Tsutsui does not falter and she is very protective of him. Tsutsui highly regards her as a "good person", and she is one of his best friends (next to Ito). Iroha forgets about tsutsui after her surgery and is now in Los Angeles her unrelated sibling proposes that he loves her. She saw a keychain which is from the cultural festival seven years ago and remembers something. When she meets Tsutsui with the same Keychain she asked why Tsutsui has the same keychain as her Tsutsui says it maybe was common back then. At the end of the series, they end up getting married and the following year after their marriage, she falls pregnant.