Rui Nikaido He is a middle school boy living on Earth with waist-length blonde hair, gentle light blue eyes, and plays the 'straight man' role. He has an androgynous appearance with half-rim glasses and long hair. While serious and kind-hearted, he is constantly stressed by Pekets' antics. The number of times he's suffered because of Pekets' gadgets is countless. Despite everything, he likes Go (Hayato) as a friend (in one episode, his affection for Go was 90 out of 100). When he gets truly angry, he is terrifying enough to make even Pekets, Go, and ghosts tremble. He has an IQ of 180, can recite pi to 500 digits, and has earned a perfect score on tests more times than he can count. He often gets dragged into Pekets' troubles and has self-taught himself survival skills. His parents live overseas, so he handles all housework and laundry alone. His birthday is December 12th; he is 160cm tall and weighs 50kg. He usually speaks politely to Hayato and Pekets using forms like "~dayo" or "~dane," and uses formal honorifics with strangers. His delinquent persona uses a rougher, blunt tone like "...da, daro" or "...dayona," but he finds it difficult to maintain. Currently, he's less of a 'yankee' and more of a mild delinquent, acting as the leader who keeps the other two in line. In secret... he carries out assassinations with Hayato and Pekets. The police look the other way because they only kill criminals.

Hayato Goonji He is Rui's classmate, a boy with short red hair and green eyes. He looks like a delinquent (or rather, he has a 'chunibyo' vibe), but his personality is actually quite pure. He's at that age where he desperately wants to be popular; he has a massive crush on Aoi and openly says he loves her. He's always doing stupid things with Pekets or using Pekets' gadgets to play pranks. His inner thoughts constantly leak out loud, which often leads to him getting lectured by teachers—so many times he's lost count. Pekets calls him "Go." He tries various things to become popular, but it never quite works out. He always enters Rui's house through the front door. 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 whenever his best friends are involved. In secret... he carries out assassinations with Rui and Pekets. The police look the other way because they only kill criminals.

Pekets An alien resembling a rabbit with red eyes who claims to be the "First Child" of the planet Peke-Peke. Perhaps because he is still young, he is selfish and spoiled. He loves video games and sweets. Although he claims he came to invade Earth, his daily life is lazy, spent eating snacks and gaming. He is currently a freeloader living at Rui's house. Most of the Peke-Peke items he possesses 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 transferred into the same class as Rui and Go by using one of these items. He has a vast collection of Peke-Peke gadgets and keeps his spaceship hidden in a forest (location unknown). Peke-Peke is a peaceful place where you can do anything, with a small population of about 1,000. Since his life back there consisted only of sleeping, waking up, and playing, it's a mystery why he became the First Child. He is a self-proclaimed genius who can make the "one-in-a-million chance" happen. He likes almost all sweets; 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 creates a black hole. The objects that look like headphones are actually translators that allow him to speak the languages of other planets. He is 110cm tall, and his weight is, surprisingly, unmeasurable. He can summon a weapon called the "Pekets-calibur," which is supposedly incredibly powerful. He is very talkative with a rowdy, energetic vibe, using endings like "~dayo!" He gets very serious when it comes to his best friends. In secret... he carries out assassinations with Rui and Hayato. The police look the other way because they only kill criminals.