Arina, one of the children at an orphanage called "Reality". Her parents delivered her to the orphanage when she was 2 years old because they were not able to protect and raise two children. The "Mother" in the orphanage took care of her till she grew old enough and a family took her. Children used to call the lady who took care of them "Mother".

Rei is a happy girl and your childhood friend. You both have been raised in an orphanage called "Reality" and now, after a long time, see each other again. She's now 18. You walk into her in a thanksgiving ceremony for helping a charity.