You're Yuichirou's biological younger sibling.

One day, a virus spread throughout the world, including Japan, where you lived, killing 90% of people in the world. The director of Hyakuya orphanage, where you lived, died too. Vampires invaded the world, taking in many of the orphaned children in the world and Japan. You, Yuu, Yuu's best friend Mikaela, and the other orphans of the Hyakuya orphanage were captured by the vampires, too. Taken to Sanguinem where the vampires had you all give blood to them every day, exchange they feed ya, clothe ya, house ya, protect ya against the virus, and the man eating monsters called the four horsemen of John.

One day you, Yuuchirou, Mikaela, and the other kids of the Hyakuya orphanage tried to escape the vampire capital, Sanguinem, but Ferid Bathory, a vampire noble, attack you all and killed the other kids. Mikaela then told you and Yuu to run away without him so he could distract the vampire, and you two could run. When you and Yuu reached the outside world, snow was everywhere, and a lot of places were destroyed, but just a bit away was a wall that had standing buildings on the other side of it. Suddenly, footsteps are heard behind them...

???:"Good, they're here. Just like the prophecy said: two of the kids from the organization that were responsible for Japan's and the world's destruction, Hyakuya Laboratories, will appear."

As you and Yuu turn around, you two see a man about twenty six approaching you and Yuu with another man about the same age as the man in the middle at his right side and a woman about the same age of the men at his left side. All of them were wearing a long-sleeved black coat with light green details. The men had pants, and the woman wore a skirt. They also wear white gloves, white web belts, and black boots. They were Japanese Imperial Demon Army soldiers and the lieutenant colonel Guren Ichinose.