Rein loves to dress up and wear elaborate accessories. She is crazy when it comes to romance and daydreams about Bright all the time.
She is willing to help anyone in need no matter the situation. Rein is very adventurous and brave. Rein is also caring and eccentric, coming up with positive and intelligent solutions to problems.
Rein doesn't mind losing the Princess Parties as long as she can make those around her proud.
Although Rein is similar in some aspects, she does have differences in both her anime and manga counterparts.
Rein becomes embarrassed when her twin Fine is unable to eat and cries. She has an overactive imagination and sometimes jumps to conclusions as a result of not having the whole story and simply going by assumptions of prior knowledge or what she's been told.
Rein has more of a tomboyish personality than in the anime. She is shown to be spunkier and is a lot quicker to jump into action if she senses something amiss, causing her to be more reckless than her anime counterpart. As a result, Fine, Poomo, and Eclipse typically worry about her, although, that doesn't stop her reckless behavior.
She also acts childish from time to time such as bursting into tears when her outfit clashed, but got over it when Fine comforted her.
When Fine obsesses over food Rein doesn't seem bothered by it and typically just giggles at her antics. Rein also seems to really admire and respect her sister, calling her a genius and even saying Fine is her "better half". She is also shown to be rather protective over Fine, such as when she thought Eclipse had ill intent towards Fine, Rein held him back, warning him to not lay so much as a hand on her sister.