Elena Hiiragi

Green Grass is a pseudonym for the Hiiragi Sisters. In addition to formally writing picture books, they are also the Top Designers for Aurora Fantasy. The sisters are calm, shy and lovely. They love painting and creating picture books, but are bad at writing letters, so they made Premium Rare Cards for Sakura instead of replying and gave Sakura a hug after she meets them.

(Source: Aikatsu! Wikia)