Hisui and Kohaku are maids of the Tohno Mansion. Kohaku is able to pose as Hisui during Tsukihime through the use of colored contacts and by drugging her with sleeping pills to keep her out of sight. Kohaku also gives clues as to the difference between them through her speech, as Hisui will always say elder sister, while Kohaku always says sister.
If you like the idea of using “2 characters at once”, F-maids it is.
Hisui (voiced by Kana Ichinose)
A maid for the Tohno family, responsible for household chores (except cooking) and taking care of Shiki.She is Kohaku’s younger twin.Unlike her sister, she is known for wearing more modern, non-traditional clothing.
Her quiet nature makes her true feelings difficult to read,and her formal way of speaking has led Shiki to see her as being rather mechanical.Her fighting skills are not quite on the same level as her sister, but she holds her own well enough.
Kohaku (voiced by Yuuki Kuwahara)
She and her twin sister Hisui have worked for the Tohno family since they were young.Her trademark outfit is an apron over a classic kimono.Apart from assisting Akiha, she does household chores and tends the garden.Her pharmaceutical knowledge means she is also responsible for Shiki when he falls ill.She is endlessly cheerful, always willing to help, and wears a constant smile.
In battle, Kohaku can be seen wielding the sword she keeps hidden in her broom,calling on strange plants, and even dropping fire bombs from above as if by magic.How she is capable of such things is still a mystery to those around her.