Illustrator Comment:

"I designed Irene and Sophia as an odd couple. Irene is tall and has a gentle personality, while Sophia is on the short side, yet she’s a hard worker that energetically accomplishes everything she sets her mind to. Normally, Sophia shows her reliable side through her knowledge for formulating plans, however, since Irene is actually the psychological pillar of these sisters, they are indispensable and irreplaceable for each other.”

Translation via YGOrg