Hero Circle () is a Korean animated series produced by Studio TNT and the Educational Broadcasting System. The series aired on EBS1 every Monday and Tuesday at 5:45 pm, beginning on June 29, 2020. It aired on Tooniverse every Wednesday at 6 pm, starting on July 29, 2020. Season 2 was first broadcast on June 29, 2022, airing every Wednesday at 7 pm, and later at 5:30 pm.
Plot The series is set at a high school in a futuristic city called Popo School (named Cityside Academy in the English dub), following the misadventures of a group of five kids with superpowers called the "Hero Circle". They include Teo, the mischievous leader of the club who has telekinesis; Vincent, a timid vampire who can transform into a bat; Sena, a cynical and competitive girl who can run at the speed of light; Lucky, a cheerful angel; and Dino, a scientist who transforms into a dinosaur when he is angry.
Season 1 shows incidents that occur between supporting characters in various clubs at the school, with other students coming to the Hero Circle for help. Season 2 expands the world view, with episodes in which the Hero Circle competes in sports competitions with a rival school named Caesar School, takes a time machine to the dinosaur era, and confronts real villains, though the formula of season 1 is still kept.
Characters Main characters Teo () (voiced by Cho Hyun-jung) is the mischievous, self-appointed leader of the Hero Circle. He can freely move light objects using telekinesis. Because he is always motivated, he expands his work and gets criticized by his friends, but he is not discouraged and is always full of confidence. Sena () (voiced by Yeo Min-jeong) is a blue-haired girl and a member of the Hero Circle. She is a competitive person with a burning desire to win when her pride is at stake. She uses her ability to move at the speed of light and excellent athletic skills to help others. She is very interested in social networking services, spending most of her time on her cell phone. Vincent () (voiced by Yang Jeong-hwa) is a timid and cowardly vampire and a member of the Hero Circle. He has the ability of immortality, but does not want to fight anyone. Unlike ordinary vampires, he is a non-vampire and a pacifist who gets along with humans. He can also transform into a little bat. Marvin was originally planned to be a main character with the ability to become invisible, but was later replaced with Vincent, who inherits Marvin's timid personality. Lucky () (voiced by Jeon Hae-ri) is a little angel, and a member of the Hero Circle, who is always happy and full of laughter. She remains cheerful and positive regardless of the situation or events occurring. She does whatever she wants, which sometimes leads to her getting into trouble. Whenever she is in danger, her omnipotent father from Heaven, God, appears to help her. However, Lucky herself does not know this fact. She likes fluffy things. Dino () (voiced by Kim Eun-ah) is a cynical genius scientist and a member of the Hero Circle. He has great intelligence, excels in school, and often creates inventions. He is usually calm, but when he gets angry, he transforms into a giant dinosaur. According to early concepts, he accidentally gained this ability while trying to develop a height-growth potion.
Science Circle Teslee () (voiced by Jeon Tae-yeol) is the leader of the Science Circle. He always loses to Dino in exam scores and is in a perennial Kong-line (), coming in 2nd place. Ed and Ned () (voiced by Kim Myeong-jun and Um Sang-hyun) are members of the Science Circle.
Garden Circle Debbie () (voiced by Jang Ye-na) is the leader of the Garden Circle, who resembles Anne Shirley. She catches students who ruin or invade the club and forces them to work in the garden, using them as slaves.
Robot Circle Black, Red and Blue () (voiced by Cheon Ji-seon (Black), Kim Eun-ah (Red; first voice), Jeon Hae-ri (Red; second voice) and Lee Sang-jun (Blue)) are members of the Robot Circle, with Red as the leader. Kane () (voiced by Um Sang-hyun) is a member of the Robot Circle. He is said to have previously participated in a track and field competition with Caesar School, but lost and transferred to the school. He faces Teo, Sena and Vincent alone, using various fouls and gaining the upper-hand with his flying abilities, but is defeated by Sena. He quits, effectively giving up on track and field. However, he is scouted by the Robot Circle, who was watching the game, and he joins the club in a green position.
Manga Circle Bonnie () (voiced by Kim Eun-ah) is the daughter of a vampire hunter and the leader of the Manga Circle. She has a fear of bats. In season 2, she has a crush on Vlad, Vincent's cousin, drawing a manga about him and herself, although she denies it. Mako and Yuko () (voiced by Cheon Ji-seon) are Japanese twin sisters and members of the Manga Circle. Mako wears square glasses, while Yuko wears round glasses. They use honorifics for Bonnie, the club's leader, and have a good relationship with her. They are shown to like heavy metal, as they are seen waving cheering sticks during band performances.
Band Circle Marvin () (voiced by Kim Myeong-jun) is the lead vocalist and guitarist of the Band Circle. He was originally planned as a main character in the Hero Circle, with the ability to turn invisible. Despite being in a band, he would have suffered from stage fright and could only perform properly when he is invisible. He was later replaced with Vincent, who inherits Marvin's timid personality, and the invisibility concept was used as the name of one of his songs, "Invisible Man". He has a crush on Yuko from the Manga Circle. Duke, Chester and Simon () (voiced by Jeon Tae-yeol, Lee Sang-jun and Um Sang-hyun) are members of the Band Circle, with Chester as the leader.
Computer Circle Bow Jr. () is Bowstein's mischievous son and the leader of the Computer Circle. Due to becoming less talkative, he communicates via text message. Timmy, Andy and Choco Nara Strawberry Gongju () (voiced by Um Sang-hyun (Timmy; first voice), Cheon Ji-seon (Andy), Jeon Hae-ri (Choco Nara Strawberry Gongju) and Park Joo-gwang (Timmy; second voice)) are a trio of computer science truant students who hack into the school system. Dino tracks them down, and in the end, Timmy and Andy are captured by Sena, while Strawberry Gongju escapes. Timmy uses the nickname Power Supreme Genius () online and an avatar with blue hair and a mask; Andy uses the nickname Mr. Baby Duck () and a green duck avatar; and Strawberry Gongju's real name is unknown, but she uses a princess avatar in a crown and dress with twin tails. Strawberry Gongju's name is based on the Korean chicken and pizza brand Pizza Nara Chicken Gongju.
Detective Circle Doyle () (voiced by Jeon Hae-ri) is a detective and the leader of the Detective Circle. He is named after Arthur Conan Doyle, is a parody of Sherlock Holmes, and wears a bowtie similar to Shinichi Kudo from Detective Conan. Kin () (voiced by Park Joo-gwang) is a talking parrot owned by Doyle.
Occult Circle Occul and Cult () (voiced by Um Sang-hyun and Jeon Tae-yeol) are members of the Occult Circle, who summon beings from another world using a book. Occul has orange hair, and Cult has turquoise hair.
Demon World Cala and Mitty () (voiced by Yoo Bo-ra and Lee Bo-yong), also known as the Calamity Sisters (), are a duo of disastrous fairies and arch-nemeses of Lucky, who grant people's wishes in exchange for taking their souls. Lilith () (voiced by Lee Ji-hyun) is the princess, arch-nemesis of Teo and heiress of the Demon World. She aims to bring bad luck to people and make them unhappy. Demon () (voiced by Jeon Tae-yeol) is the king of the Demon World and Lilith's father. He is based on Hades in Greek mythology.
News Circle Oliver () (voiced by Shin Yong-woo) is a newspaper editor in the News Circle, who likes grapes.
Cheerleader Circle Cindy, Stephanie and Wendy () (voiced by Kim A-rong (Cindy; first voice), Yeo Min-jeong (Stephanie) and Cheon Ji-seon (Cindy; second voice, Wendy)) are a trio of cheerleaders and members of the Cheerleader Circle, with Stephanie as the leader and sometimes an extra. The total number of club members is unknown. A fourth unnamed member is occasionally seen, finally appearing as a supporting character in episode 7 of season 2.
Cooking Circle Murphy () (voiced by Jang Ye-na) is a cafeteria manager and the leader of the Cooking Circle.
Game Circle Eugene () (voiced by Kim Chae-ha) is a calm, laidback boy and the leader of the Game Circle, who first appeared in episode 24. He wears a scouter, which is used as a scanner to detect Papa Cat's robot's weakness in the final episode of season 2. He also stores bigger items in his pocket, from video game consoles to game chips and even remote controls. Steve () (voiced by Um Sang-hyun (first voice) and Lee Sang-jun (second voice)) is a fat boy and a member of the Game Circle, who collects figures as a hobby. He appears as a missing member in the in-universe virtual reality game called Hero Fantasy. Although his name was not revealed, fans called him "Steven" due to his appearance resembling that of Steven Universe. Studio TNT noticed this, and gave the character the name "Steve".
Book Circle Jennifer () (voiced by Yang Jeong-hwa) is a blue-skinned librarian and the leader of the Book Circle. She first appeared in episode 20. Because of her gloomy atmosphere and mysterious return date announcements, she becomes the main character of ghost stories that circulate around Popo School. Jennifer personally goes to inform of books that are due, seemingly indicating her diligence in club activities. She appears in a ghostly manner throughout the episode until her identity is revealed. She is also revealed to be an acquaintance of the Occult Circle. In episode 19 of season 2, she comes to the Hero Circle for help because everyone is increasingly afraid of her. Everyone agrees that it would be good to change her image, so she goes to the Manga Circle for help. The Manga Circle changes her costume and makeup, giving her the pretty star cosplay of "Jupiter". However, because of the high synchronization rate, she becomes too popular, so she eventually goes back to her original state, thinking that her own appearance is better. Jennifer later becomes close to someone who had not been afraid of her before. It is not revealed who that person is, and only their silhouette is shown, but the silhouette and voice are obviously that of Eugene. The ending credits even reveal Eugene's voice actress Kim Chae-ha.
Breeding Circle Teddy () (voiced by Kim A-rong) is a lion who works in the Breeding Circle, and one of the two anthropomorphic animal students to attend Popo School, the other being Ketchop. He first appeared in episode 12 of season 2. He specializes in parkour, and he catches a mother horned rabbit several times bigger than himself using only tree vines. The Horned Rabbits () are rare animals raised in the Breeding Circle. They are called horned rabbits because theirs ears resemble horns. Unlike regular rabbits, they like to eat mushrooms instead of carrots.
Theater Circle Charlie () (voiced by Cheon Ji-seon) is a theater director and the leader of the Theater Circle. She is also shown to be an actress, even when she is dying, becoming a different person when doing so. She casts the Hero Circle in the play, but they all have very bad acting skills. In response to the terrible reaction from the other students, she steps in as the real prince and revises the script, successfully finishing the play.