Kojou Akatsuki (暁 古城 Akatsuki Kojō?)
Voiced by: Yoshimasa Hosoya
Kojou was a normal 16 year old high school student 3 months prior to the beginning of the story, until becoming the 4th progenitor after his predecessor, Avrora Florestina inserted her spirit into his body as the result of a wish. He claims to remember nothing of the incident. When aroused, his blood lust takes over and the only way to satisfy it is to drink his own blood, usually from the nosebleeds he experiences. As a vampire, Kojou possesses superhuman strength, speed, reflexes, and durability, but has far greater power than that of a normal vampire due to his status as a progenitor. He has also inherited Avrora's twelve familiars. Due to never having drank human blood, Kojou at first has no control over his powerful familiars, but after drinking an individual's blood, one familiar will acknowledge him as its master. By drinking the blood of others who have familiars, he is able to gain control over their familiar. By volume 9, he is able to control 6 of the familiars. Kojou is also lacking the 6th, 10th and 12th familiars, the 12th being in Nagisa and the 6th and 10th still have their human bodies. In Strike the Blood EX, he has two daughters (in the future), Reina from Yukina and Moegi from Asagi.
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Reina Akatsuki (暁 零菜 Akatsuki Reina?)
Voiced by: Kana Asumi
The daughter of Yukina and Kojou in Strike the Blood EX. She is identical in appearance as her mother (in youth), except with a bigger bust and wields a golden lance as her familiar. She also inherited her father's abilities as a vampire and the tendency to get nosebleeds when she gets excited. She has the same eyes as her father. She is also a half sister of Moegi.
Moegi Akatsuki (暁 萌葱 Akatsuki Moegi?)
Voiced by: Minami Tsuda
The daughter of Asagi and Kojou in Strike the Blood EX. She bears a similar resemblance to her mother. She is also Reina's half sister.