Iori Nagase/Story Plot

Spoilers below

Hito Random arc
Due to her questioning of who her "original self" is, the swapping body phenomenon makes her worry if people can still identify her even if she's not in her true body. After an interference by Heartseed, Iori is left in critical condition at the hospital. Believing she is going to die, Iori (while in Inaba's body) shares her first kiss with Taichi.

Kizu Random arc
Becomes slightly concerned when people fail to realize any deviations from her usual self even when her 'Impulses are Unleashed'. Later realizes Inaba has fallen in love Taichi and encourages her not to hide her feelings.

Kako Random arc
Takes advantage of the phenomenon by striving to find her original self while she was still a child and not yet altering her personas. She is later made an offer by Heartseed to return back in time to any age to redo her life. Iori eventually settles her crisis with her second stepfather by admitting to her mother that she does not need a father to be happy.

Michi Random arc
Undergoes a drastic change in personality when she begins believing that people only like her for her cheerful persona and do not understand her true self. Iori starts questioning her own feelings towards Taichi and rejects his confession because he only sees the ideal version of her. The 'Sentiment Transmission' phenomenon reveals her inner bitterness and as a result, Iori begins alienating herself from her friends. Her hostility indirectly causes the StuCS's club presentation project to be vandalized. Eventually, Iori chooses to stop caring about finding her original self and instead chooses to follow her feelings and live freely. She later proves instrumental in saving Inaba who was kidnapped by thugs and subsequently makes amends with her friends.