After Shuichi Akai Became Rei Furuya's Childhood Friend-Tamer

After a long struggle, the conflict between the Black and Red sides reached its final showdown. After Rei, Shuichi Akai was reborn, just before the light appeared. When he opened his eyes, he found himself in an unfamiliar place, and his body had become smaller. Then he saw a familiar figure with blond hair and dark skin.

Theme: Save the characters whose stories ended in heartbreak.