Introduced in Episode 11 of Season 1, there is a trio of girls who attend the same class as the main characters. One has short dirty blonde hair and glasses, Sumae Mizuno, another has medium length red hair, Shijimi Chouno, and another has long black hair, Tonko Oniyama. All three of their names are puns on their true identities as Insect monsters: Shijimi as a Lycaena phlaeas or small-copper butterfly, Tonko as an "Oniyanma" or golden-ringed dragonfly and Sumae as a Whiriligig Beetle.
They are introduced distributing a rival newspaper called 'Youkai Square" as part of a new newspaper club called "Super Newspaper Club", all to the irritation of Kurumu. Upset at the possibility of being shut down due to lack of popularity, Kurumu and Yukari try to spread their newspapers to students wearing cute maid outfits, but the trio upstages them again by wearing swimsuits and offering free photos of themselves to anyone who subscribes.
Gin reveals that these girls, and a girl named Keito who seems to be with them, appear to have the backing of the Safety Commission. Fearful of them shutting down the Newspaper Club as they did before, and other clubs who've stood in their way, Gin tells the group to burn all the newpapers they've made. Kurumu is unable to go with it as she considers them treasures and the first thing ever did with people she now considers to be her real friends. In particularly Tsukune who she considers to be her Destined One.
Seeing this, the trio laughs and calls them "crappy newspapers", calling for Keito and asking her to deliver punishment. Keito reveals her true colors and that the 'Super Newspaper Club' is in fact part of the Safety Commission. Tsukune tries to reason with her, but Keito is adamant on the "justice" that she and her club enforces on the school. She begins to burn the newspapers while the trio holds Kurumu back. Keito ensnares all of them in web before revealing the truth: the trio were all part of previous clubs who similarly resisted the Safety Commission. Tonko was from a small and "boring" Literature Club, Shijimi was from the Japanese Tea Ceremony club, and Sumae was from the Yaoi Manga club. Keito, much like a real spider to the bugs they are, ensnared them in her webs and injected them with her spider venom. This caused all three of them to become her loyal and devoted servants. Keito prepares to deliver the same punishment to Kurumu, but is rescued by arrival of Mizore, Moka, and Yukari. Tsukune manages to remove Moka's rosario, unleashing Inner Moka. Despite trying to stop her, Kurumu manages to free herself from the webs, ensnaring the trio once more in Keito's webs. Keito attempts to ensnare Inner Moka, but she turns the tides and fiercely kicks her into her own webs along with the trio, defeating her.
Keito and the Trio do not make any further appearances in Season 1, but this act against the Safety Commission causes Kuyo to take action against the Newpaper Club before his own defeat. In Season 2, the Trio make several small appearances throughout the season. Although they seem to be free of Keito's control as they are no longer with her at any moment, they still serve as minor antagonists, such as when they tease Mizore and her cooking skills in Episode 5. They do admit however that her new dish tastes pretty good at the end. They themselves make their own curry dishes which they serve to a group of appreciative boys and are very pleased by this, telling them they worked really hard on them and to eat lots of it. They purposely continue to wear short skirts in Episode 8 despite Ruby's new rules. They tease her new rules, leading the irritated witch to give them an electric shock with her magic. Collapsing on top of each other, they finally reveal their names. They briefly appear in Episode 3 waiting for their physical examination, remarking how they've skipped meals in preparation for it. They join the field trip in Episode 9 where they can be seen in winter uniforms. In Episode 10, they are very attracted to the handsome Kōtarō Ijūin much like all the other girls. They ask if he'd like if they could guide him to their next class as he wouldn't know as a new student and begin gushing in excitement when he agrees. He entrances them with his magic, causing all three of them to proclaim "we'll devote our whole lives to being there for you!". This marks the second time in a row where they've been brainwashed in the series, though this is shortly lifted by Kokoa and Moka defeating him (revealing him to be Ko) and breaking the spell on all the females at school. They also briefly appear in Episode 11 under the control of the Lilith's Mirror. The Mirror has the ability to unleash, not just the monster form of any student in disguise, but also bring forth their true nature. To Tsukune's friends, this all meant their attractions to him went out of control and they became very lascivious. To the Trio, they are transformed into their Bug Monster forms and starting fighting with other students who are similarly acting belligerent toward them. They make their final appearance in the last episode, dancing with each other and all the students as the series end.
Overall, despite being a bit mean and airheaded given how many times they've been hypnotized, they are three well-meaning girls and best friends with each other. It is unknown if they knew each other prior to Keito enslaving them, but given that they are all Insect monsters and of a similar personality, it's likely that they did despite all three being part of different clubs.
