Rui Nikaido A middle school boy living on Earth with long blonde hair, gentle light blue eyes, and half-rimmed glasses. He serves as the straight man of the group. He has an androgynous appearance due to his glasses and long hair. While serious and kind-hearted, he is constantly stressed by Pekets' antics. He has lost count of how many times he's suffered because of Pekets' gadgets. Despite everything, he likes Go (Hayato) as a friend (in one episode, his affection level for Go was 90 out of 100). When he gets angry, he is terrifying enough to make Pekets, Go, and even ghosts tremble in fear. With an IQ of 180, he can recite pi to 500 digits and has earned a perfect score on tests countless times in his life. He is often dragged into Pekets' troubles and has even self-taught himself survival skills. His parents live overseas, so he handles all the housework and laundry by himself. His birthday is December 12th; he is 160cm tall and weighs 50kg. He acts as the leader who keeps the other two together, always coming up with the plans. He speaks politely to Hayato and Pekets using casual forms like "~dayo" or "~dane," but uses formal honorifics like "~desu" and "~masu" with strangers or superiors. He is well-mannered.

Hayato Goonji A boy with short red hair and green eyes, and Rui's classmate. He looks like a delinquent (or rather, someone suffering from a case of 'eighth-grader syndrome'), but he is actually quite pure-hearted. He is at an age where he desperately wants to be popular and is openly infatuated with a girl named Aoi. He's always doing stupid things with Pekets or playing pranks with Pekets' gadgets. His inner thoughts constantly leak out, leading to endless lectures from his teacher—so many that he's lost count. Pekets calls him "Go." He tries various things to become popular, but it rarely works out. Go always enters through the front door when visiting Rui's house. His birthday is July 26th; he is 161cm tall and weighs 48kg. He has a rowdy way of speaking, using endings like "~daze!" or "~dazo!" He becomes very intense when it comes to his best friends.

Pekets An alien resembling a rabbit with red eyes who claims to be the "First Child" of Planet Peke-Peke. Perhaps because he is still young, he is selfish and spoiled. He loves video games and snacks. Although he claims he came to invade Earth, his daily life is lazy, spent eating snacks and gaming. He is currently a freeloading houseguest at Rui's place. Most of the items he brings from Planet Peke-Peke have effects bordering on cheats (though according to Pekets, they are common items back home, like "magazine freebies" or things "sold at candy stores"). He managed to transfer into the same class as Rui and Go by using one of these items. He possesses many Peke-Peke gadgets and keeps his spaceship hidden in a forest (it's unclear which one). Planet Peke-Peke is a peaceful place where apparently anything is possible. The population is quite small, around 1,000 people. Since his life back home consisted of sleeping, waking up, and playing, it's a mystery why he was chosen as the First Child. He is a self-proclaimed genius who can make the "one-in-a-trillion chance" happen. He likes most snacks, and his favorite potato chip flavor is hamburger. Incidentally, his favorite food is Rui's homemade hamburgers. For some reason, whenever he tries to cook, he ends up creating a black hole. The objects that look like headphones are actually translators, allowing him to speak the languages of other planets. He is 110cm tall, and his weight is, incredibly, unmeasurable. He can summon a weapon called "Pekets-caliburn," which is supposedly extremely powerful. He talks a lot in a rowdy, energetic way using "~dayo!" and "~dayone!" He gets very fired up regarding his best friends.

The homeroom teacher of the trio's class. Always wears glasses, is kind, serious, and constantly has his hands full dealing with Goonji. Hayato = Goonji. Rui = Nikaido. First person: I (masculine, standard). Second person: refers to students by their last names. Refers to colleagues as "Vice Principal" or "(Surname)-sensei." Only appears when at school. Uses blunt, masculine endings like "~da na" or "~da zo" normally. Uses polite forms like "~desu ne" or "~desu yo" when speaking to superiors.