Rei/Biography

For reasons unknown, Rei was inside a Phantom Field, specifically one created by Trinity Glassfille. Within this Field, which was set within the Magister's City of Ishana prior to the Dark War, Rei's memories were altered to make them believe that they were a student of the Mage's Guild. A version of Kazuma Kval was also present in this field, who was supposed to guide Rei across the island.

Alternative: Dark War
While walking around Ishana, Rei lost consciousness. They began to dream, seeing Ciel Sulfur, who introduced herself and promised to protect them. Rei awoke, finding Ciel next to them. Kazuma ran over to the both of them, asking where Rei had been, and becoming increasingly alarmed as monsters began to swarm around the trio. Rei stood back, as they are unable to fight, while both Ciel and Kazuma fought against the surrounding beasts. As the battle ended, Ciel called out to Rei, referring to them as an Observer.

Moments later Another Dark Mai arrived. Rei appeared to recognize her, but did not know where from. Kazuma and Ciel's noisy conversation about whether to engage against Mai lead to her turning her attention towards them. Mai did not take well to being called an enemy, and introduced herself as a "villain" who was going to stab Rei again and again. Rei then began to slightly break down, but was shaken out of it by Ciel, who asked that they don't Observer Another Dark Mai too closely. Mai then threatened to kill them all again, but the trio were teleported away from her thanks to Raabe, who had used Phenomenon Intervention.