Sekirei: No 04

Height: 174 cm

Weight: 59 kg

Three sizes: B 85 / W 63 / H 91

Ashikabi: Natsuo Ichinomi

Norito: Currently Unknown

Karasuba, Sekirei #04, is the leader of the 'third generation' Disciplinary Squad.

She is also known as the "Black Sekirei" and "MBI's dog." In the past Karasuba was a member of the "first generation" Disciplinary Squad and teamed up with Yume in the "second generation" Disciplinary Squad. She seems to know a lot about Musubi's past and knows about many parts of the Sekirei Plan from her job and from the fact that she has been around as long as Miya, Matsu, or Kazehana. Karasuba and Miya Asama do not associate well with each other (Miya not allowing her to set foot in Izumo Inn) and tend to come close to fighting at the mere appearance of the other. Her name (karasu+ba) means "raven feather" literally.

Karasuba still wears the uniform all members of the first generation of the Disciplinary Squad were equipped with. A Tight black leather top, a miniskirt and stockings. Over the shoulders wearing a gray cape with the Sekirei Crest printed on it. She has long dark blonde hair and gray narrow eyes.

It appears that Karasuba desired to fight and defeat Yume, and as a result, resents Yume for "disappearing" before they could settle their rivalry. This unsettled matter appears to heavily influence Karasuba's actions throughout the story and her behavior towards Musubi who received Yumes Tama at some point in history. She maintains a "friendly" relationship with Musubi (whom she calls "Mu-chan"), and the two have made a promise to be the last two Sekirei standing. She gets easily excited if she meets a strong opponent to the point that she wants to cut down other Sekirei so she can lose some steam. Karasuba believes humans are a weak and insignificant race and looks down on them(though she surprisingly gets along very well with her Ashikabi). She seems very bloodthirsty as she attacks and terminates two Sekirei (Mitsuha and Ikki) because she is in the mood for it.

Not much is known yet about Karasuba's strength except that her weapon of choice is a Japanese Long-Sword and that she is feared by many Sekirei. Matsu once stated that if Miya and Karsuba would engage in a fight, half of Tokyo would be destroyed in the process. Her only shown fighting scene seen so far was against Mitsuha who was no match for her and easily got terminated by Karasuba. Seeing this the fairly powerful Akitsu decided to run away. Unlike Miya, who has been shown to be able to split a battleship while at a distance, Karasuba has so far been shown to actually need to make contact with what she is attacking.

Karasuba is the only steady member of the Disciplinary Squad throughout all generations. Like all Members of the first generation Disciplinary Squad she was adjusted by Takehito Asama. In her time with the first generation of the Disciplinary Squad she participated in the fight on Kamikura Island. She is seen there cutting down a retreating soldier, holding his bloody corpse with her right hand, wielding her sword in the left, refusing to let the invading troops retreat. Just asking if they really thought that they can just leave after invading the island.