A sister by blood to Naoto. Unlike Naoto, who is uninterested in the Terumi bloodline, Saya takes pride in it.
Born to the Terumi branch, Saya was given martial arts training by her mother. When she was 8 years old, the parasitic Drive, Soul Eater, latched onto her. The young girl went crazy, killing her father and every other member of the clan except her brother, Naoto. Before Saya could kill anyone else, the head of the Amanohokosaka Clan, Mei Amanohokosaka, intervened and kept Saya detained for the next 5 years within the main Amanohokosaka household.
Bloodedge Experience - Part 1
Mei eventually let Saya go under the pretext of being unable to control her much longer. She gave Saya a letter for Naoto, and the young girl went to Shin Kawahama City to find her brother. She eventually arrived at her brother's flat, and the door was opened by her cousin, Haruka. Haruka left to get Naoto from the living room and the two siblings were finally reunited.
Bloodedge Experience - Part 2
Saya was invited into Naoto's apartment, and rejected Haruka's offer of black tea. She asked who Raquel Alucard was and what the contents of the letter were. As soon as Haruka left with Raquel, Saya grabbed Naoto by the throat and pushed him against a wall, telling him how desperately she wanted the Eye of the Hunter. She began to drain his life-force, but she noticed something was odd until Raquel came bursting back into the room and use her Drive to push the siblings apart. Saya drew her blade and lunged towards Raquel, drawing the vampire's blood. She learned that Naoto had already been killed once and relented on attacking again, instead leaving, claiming that she had only arrived to deliver the letter.
At some point, Saya ran into an Apostle and murdered him using Soul Eater and her sword. The corpse was later found by Spinner Superior. Soon enough, Saya found Valkenhayn R. Hellsing and Relius Clover, attacking the former for the "sin" of killing Naoto. The fight was grueling, although it leaned heavily in Saya's favor as she attacked with a technique that allowed her to amplify her speed and power. After several minutes had passed, however, Saya was too tired to fight, the trade-off for the technique. Even though she had activated her Drive, Saya was about to lose, only for Naoto to come to her to rescue. Before the new brawl could ensue, Spinner arrived and kidnapped Saya.
As Saya had been kidnapped, she was encased in a large insect created by Spinner. The girl was unconscious, her Drive being allowed to run rampant. After a long fight, Raquel and Naoto defeated the bug and Saya was allowed free. The fight with Spinner, however, was not over, and in the chaos that followed, Relius and Valkenhayn kidnapped the girl. They took her back to the Mitsurugi Agency and kept her contained.
- BlazBlue 10th Anniversary Site (JP), Saya Terumi
- BlazBlue: Bloodedge Experience - Part 1, Chapter 6 - Interlude
- BlazBlue: Bloodedge Experience - Part 2, Chapter 7 - Siblings
- BlazBlue: Bloodedge Experience - Part 2, Chapter 9 - Interference
- BlazBlue: Bloodedge Experience - Part 2, Chapter 10 - Encounter
- BlazBlue: Bloodedge Experience - Part 2, Chapter 11 - Fusion
- BlazBlue: Bloodedge Experience - Part 2, Outside Chapter - Fragment