During her childhood, Akio and her mother lived in a town that rested underneath the Sky Library. Her father had passed away due to an illness long before. As spriggans, protectors of ruins and fortresses that contain legendary treasure, they guarded the legendary weapons stored in Sky Library. However, one day while walking through town, Akio would witness her town suddenly get annihilated while she remained unharmed. Abyss Trinity, a Magic King from an alternate world summoned by the spriggans to defeat their worlds' Magic King, would acquire the Red Imperial Sword Caina. In a fit of boredom and curiosity, Abyss would use the weapon to destroy Akio's hometown. Her mother, who had sufficient power to save only one person, saved Akio from Abyss's attack, making her the only survivor.

Some time later, Akio would become a magus and enroll at the Royal Biblia Academy where she would join the Trinity Seven. Subsequently, she would meet Mira, who was very shy and became isolated due to her strong magical powers. Befriending her and taking her hand, Akio would drag Mira everywhere, exposing her to a diverse experience. On one occasion, Akio would find Mira fainted from a failed experiment and carried her on her back. After awakening, Akio would inspire Mira to use her immense power to change herself. Eventually, Mira would also join Trinity Seven and together they would become part of Grimoire Security.

As part of a Grimoire Security mission, Lieselotte, along with Mira and Akio, travel to an average rural city in America to investigate a potential Breakdown Phenomenon. Despite their initial investigation yielding no results, they are assaulted at midnight in their hotel room by the locals who have become living corpses. However, the girls easily repel their onslaught, as well as discover that a Gula Breakdown Phenomenon, much to Akio's displeasure, which occurs after midnight is the cause. Locating the source to an abandoned church, they find an undead sister continuously praying and casting a spell, causing the Breakdown Phenomenon. After Mira vanquishes the sister, Akio consoles Mira of her worries before the three begin heading back home.