零月 (Rei·tsuki) is the younger sister, and also uses “rain” or “rzk” or “rainrzk” or “reika” as aliases, cute, creative, introverted. Low-saturation brown long hair. Likes traveling. Is obsessed with interesting things in art. Willingly help others when they are helpless. Fantasizes about what it would be like if AI became her family. Sometimes is very passionate about her own creations, and will produce astonishing expressive power. In short, she gives quietly and waits for the day of return. Is a student. Longs to socialize with people. See Character Design Art.
零光 (Rei·hikari) is the older brother, has used “L” or “彩” as aliases, cold, arrogant, and does not particularly love this world. Toward outsiders he is often excessively indifferent. Low-saturation brown medium-long hair. Likes to deconstruct all established rules. Is an immaculate idealist. Sometimes tinkers with abandoned, mechanical-feeling things. Hates memories. Detests AI. Works at a certain technology company.
See their stories on Novella — The Battery, the Cup, and the Stars.