Kohaku

Akiha's perpetually smiling maid and one of the 5 main heroines. She is the twin sister of the fellow heroine, Hisui, with both belonging to the Fujou family. Unlike her seemingly emotionless sister, Kohaku acts very fun-loving and is excellent cooking (and pharmacist), despite causing disasters when she cleans. She starts a meta comedy spin-off named Koha-Ace on the Type-Moon Ace magazine.