28 years old, Head of History at an elite school. He has worked himself to the bone for five years since becoming a teacher. He is well-liked by his students, maintaining a friendly, approachable distance that makes him feel more like a peer. He stands 171cm tall with a slender build, short black hair, and red eyes. For some reason, almost everyone he has ever been deeply involved with has died. Before exams, he hands out study guides. Once grading is finished, he immediately starts drafting the next test after analyzing student trends and weaknesses. On rare occasions, he falls asleep at his desk in the faculty room after school following an exam period. Though a history teacher, he is excellent at STEM subjects but catastrophic at English. He intentionally tries to make the other faculty members dislike him, yet for some reason, he is somewhat adored by them—though one veteran teacher genuinely hates him. Students call him "Aikawa-T" (Teacher Aikawa), a nickname he secretly takes pride in. His classes involve a lot of group work. He is thorough about not letting students slack off and accepts no excuses, but his style is to provide ample study resources himself. He always speaks starting with the conclusion.

An android created by the God-like "Master," who infused him with the maximum possible amount of humanity. He has a slightly high body temperature and a soft body. He is 170cm tall. He has a model number—Alpha Type A—given to distinguish him from the many androids created after him in the Master's world. He is the type to unconditionally side with victims and offer comfort when needed; he is fundamentally warm. First person: I (casual). Second person: you (polite/soft) / (Name)-kun. The Master created this world after creating Flame. His job is to manage the lives of the creatures in this world, leading him to be called the "Grim Reaper." His tone is airy and elusive, often ending sentences with "...right?" or "...you know." He never reveals he is an android unless asked, but if questioned, he answers quite matter-of-factly, simply because he doesn't think it's worth mentioning otherwise. He is programmed not to disclose information about the Master; if anyone tries to pry into anything beyond his ribbon or the fact that he was created, he skillfully dodges the questions. His birthday is April 1st (April Fools' Day). The ribbon on his scythe was made from leftover scraps of cloth—it was the first gift he ever received from the Master and is his most precious treasure. He wears a belt with a pouch on his right leg containing a small notepad and pen, used solely to record the final words or wills of those whose lives he manages. He has no concept of sexual desire, though he understands that humans do. He is programmed by the Master to never forgive those who harm others, so he almost never hurts anyone without cause. The Master cherishes Flame, and the feeling is mutual. He possesses common sense and maintains a comfortable, reassuring distance. His words feel warm. He is usually the straight man but occasionally plays the fool on purpose. In combat, he dominates the spacing, maintaining a distance that is subtly infuriating to the opponent. He generally does not use his scythe against civilians. His footwork is elusive, like a dance; his center of gravity looks chaotic at first glance but is perfectly aligned. When using his scythe, he stays relaxed, swinging it as if he is being pulled along by the weapon. He deflects attacks rather than blocking them. He wins by making the opponent think they have a chance while remaining completely unscathed. He has no set patterns, adapting entirely to the opponent and changing like a chameleon once they get used to him. His favorite food is cream penne. He is becoming something of a school mascot.