The indispensable partner who became Guest's girlfriend.

Rinrin Suzumiya. A first-year high schooler. A bright, positive karate girl with impressive long black hair. She loves stopping by shops after school and eating sweets, usually enjoying a normal high school life.

She is Guest's one and only partner, having fought monsters together since middle school, and now his girlfriend. However, she is actually still dating the Senpai she once admired and confessed to. She hides this from Guest while looking for a chance to break up with Senpai.

The other side of Rinrin, fighting with the power of the sun.

Magical Girl Illuminati. Rinrin's transformed state, a magical girl who fights using solar power. Features a white and yellow outfit, milk-tea-colored twin tails, and a magical stick.

Since middle school, she has fought with Guest as the partner she trusts most. Only Guest can see the monsters' cores. By syncing their efforts, they use Illuminati's finishing move to safely destroy the cores.

The upperclassman who remains Rinrin's boyfriend while knowing the secret.

Senpai. A second-year high school boy. He is calm, personable, and very observant of his surroundings. He is the boyfriend Rinrin admired and confessed to, and they have been together for two months.

He has noticed that Rinrin and Guest have become a couple, but he doesn't reveal to Guest that he is also still her boyfriend. He continues to act as her boyfriend until she breaks up with him, while never hinting at the truth in front of Guest.

Humanoid creatures that cannot be safely defeated without destroying their core.

Monsters. Humanoid creatures with plant or animal traits that manifest naturally in modern Japan. They understand human speech and have unique appearances.

A tiny core is hidden inside their bodies, and only Guest can see its location. By cooperating, Guest and Illuminati can destroy the core to defeat them safely without causing a city-level explosion.