Saji-chan no Yami Nikki

Sazi Tsukimiya gets accepted into her dream school: the school her childhood crush, Hikari-chan, attends; and she intends to make Hikari hers. However, thanks to her clumsy nature, Sazi is quickly discovered by Hikari's best friend, Mero. Mero resolves to protect Hikari while also having fun at Sazi's expense.