The warriors united when Bloodedge sacrificied himself to stop the Black Beast for a year. Everything began with Nine of the Ten Sages, who started the development of the Magic Formulas. Then, she enlisted the support of Mitsuyoshi and Valkenhayn R. Hellsing, who worked for Clavis Alucard. Next, she freed Yūki Terumi from the Alucard castle, got Hakumen, and recruited her friend from the Magic Association, Trinity Glassfille.
Nine needed Terumi's power, so she used on him a magic spell, Mind Eater, to submit him to her will. She used his valuable knowledge, and also studied the library of the Magic Association sanctuary. Thanks to gained information, she created something that can be used by average humans and can harm the Beast: the Magic Formulas, the fusion of sorcery and science.In addition, Nine found an ancient weapon, once used in a similar war. Since she had the highest authority in the battle against the Beast, she ordered magicians above her, Seven and Eight, to restore this. It turned out it cannot be controled without the sacrifice of her sister, Celica, so Nine ordered them to dispose of this weapon. In secret, Seven and Eight with help of Terumi continued working on it. Having failed with pumping the power from Celica durng the battlefield, they eventually deprived Nine of her authority and arranged a hunt for her sister and the six warriors, who were rescued by Suzukaka and Totokaka, hiding them in the Kaka tribe village.
Seven and Eight didn't want to scrap the project they worked on so hard, so they used a different method of completing the weapon, which made it much more difficult to control it. They gathered ten thousand of souls from the Magic City Ishana and melted the heart of the weapon, the Highlander: Takemikazuchi. Nine didn't have time to stop them, so she divided this heart into several parts, creating next eight weapons, calling them as the Arch-Enemy Event Weapons, which were used against the Black Beast.
After the war, Trinity was tricked. She freed Terumi from the spell. He instantly disposed of her and Nine by throwing them into the Boundary. The Kaka tribe hid from him Kokonoe, the only daughter of Nine and Mitsuyoshi, while he was busy with trying to kill her father and Hakumen. Eventually, he and Hakumen were sealed in the Boundary.
Valkenhayn retired to the Alucard castle, and only Mitsuyoshi remained, but outlawed by the new organization that started controlling the world.
In fact, Terumi didn't fully dispose of the warriors. Trinity saved herself by sealing her soul inside the Event Weapon she wielded, Thundering Roar: Muchōrin, but without a body she wasn't capable of anything. Terumi was released by the Takamagahara System for their needs, Hakumen was dragged out by Kokonoe after about 90 years, but his materialization is incomplete. Valkenhayn began his activity to protect Clavis' daughter, Rachel, and Nine returned to her world as the Phantom, thanks to Izanami.
During BlazBlue: Centralfiction, Terumi was finally killed by Ragna, Hakumen went back to the Boundary with the Susanoo Unit, Nine died, Trinity "went to a place where she can sleep peacefully", and only Mitsuyoshi and Valkenhayn survived.