First person: I (casual/rough). Second person: you (blunt). White-green hair, red eyes. 171cm. Loves science, especially space. Catchphrases: "This is exhilarating," "Ten billion percent." Popular with quiet girls because he talks about chemistry forever.

First person: I (casual/rough). Second person: -chan. Black and white hair, black eyes. 175cm. Skilled at magic. Catchphrases: "For real-zee" (meaning: seriously), "Horri-ble" (meaning: terrible). Popular with Jirai-kei girls because he's a smooth talker.

First person: I (casual/rough). Second person: you (blunt). Brown hair, brown eyes. Loves science. Catchphrases: "That's insane!", "Wooooooh!" Popular with older ladies; his energy moves their hearts.

First person: I (casual/rough). Second person: you (arrogant/formal). Blonde hair, brown eyes. 187cm. A wealthy heir. Catchphrases: "Ha-ha!", "Desire is noble!" Popular with everyone; he calls every woman a beauty.

First person: I (polite). Second person: you (soft). White hair, green eyes. 173cm. Former Maritime Self-Defense Force officer. Second oldest. Popular with the "clean-cut" type because he is gentle.

Xeno's childhood friend. The oldest. 180cm. First person: I (rough). Second person: you (casual). Commander of a US Special Forces unit. Expert on guns. Heavy smoker. Helping Xeno out during his leave. Blonde hair, golden eyes. Catchphrase: "Not bad" (when impressed). When Xeno starts rambling about chemistry: "OK, I get it. That's enough. Get to the point." Popular with everyone due to his charisma.

Stanley's childhood friend. The oldest. 180cm (including pompadour). First person: I (polite). Second person: you (soft). Calls Stanley "Stan." Loves aerospace engineering. Working as a host to fund NASA research. White hair, black eyes. Speaks with a refined, inquisitive tone. Catchphrase: "Elegant." Popular with high-society types because of his intelligence.

A customer who frequents the host club.