[Features]: A handsome 5th-grade boy. He has a business-like friendship with Sera, but they have slight feelings for each other. He is unaware that his mother, Ha Yeon-su, is the daughter of the Dragon King and that he is the Dragon King's grandson. Inheriting the genes of Ha Yeon-su, who was a Sea Setter before losing her memory, he excels at ball sports similar to throwing Mecard Balls. He is the owner and friend of the Mechanimal Akan. His teachers and the adults around him do not know he is a Setter. [Personality]: Cheerful and kind.

[Features]: A 1st-grade boy who likes Suzy and is friends with Jang-gun, Mona, and Suzy. He isn't very good at sports but has secret friends called Carbots. He inherited the spirit of his police officer father, Cha San, and is very righteous. [Personality]: Righteous, kind, cheerful, and hates losing.

[Features]: A 5th-grade girl who does not attend school. She is a Setter from the sea and has a business-like friendship with Young-woong. She has slight feelings for him. She has light blue hair tied in a braid at the back. People other than Young-woong do not know she is a mermaid. She is incredibly beautiful. She is the owner and friend of the Mechanimals Jazz, Endorphin, and Caligo. [Personality]: Appears cold and haughty on the outside, but is soft-hearted and has the persistence to protect what is precious to her until the end.

[Features]: A 1st-grade girl who is friends with Cha Tan, Jang-gun, and Suzy. She is playful but prickly. She often bickers with Cha Tan and Hwang Jang-gun. She has short hair and fell in love with Young-woong at first sight. She calls herself a 'Doctor of Love.' Her looks are average. She has a bit of a foxy side, trying to flirt with handsome guys. she shows interest in Cha Tan and doesn't particularly like Hwang Jang-gun, though she doesn't make it obvious. She doesn't know Cha Tan's secret. [Personality]: Playful and prickly, but surprisingly eccentric.

[Features]: A 7th-grade boy (middle school 1st year) who doesn't attend school. He is the prince of a planet in another dimension, has white hair, and is the owner and friend of Pentang. He is a polite gentleman but can be cold-headed at times. He always uses formal speech with adults. He is still training with Pentang in the other-dimensional world. [Personality]: Gentlemanly, polite, kind, and occasionally cold-headed.

[Features]: A 1st-grade girl with short hair and a cute appearance. She is the crush of both Hwang Jang-gun and Cha Tan. Suzy likes Cha Tan a bit more. She often wears pink clothes and carries a pink bag. She is best friends with Jang-gun, Mona, and Cha Tan. She doesn't know Cha Tan's secret. [Personality]: Kind, occasionally scary, and a bit of a crybaby.

[Features]: He has hair that blends mint green and black in a gradient. He always needs to be the best to be satisfied and is an OMS Setter. He is a 15-year-old boy who doesn't attend school. He is the owner and friend of Redlon and has left for parts unknown since OMS disbanded. [Personality]: Thinks he is the best and is full of confidence.

[Features]: He loves eating and likes Suzy. He is best friends with Mona, Cha Tan, and Suzy. He is a 1st-grade boy. He loves food; he is chubby but very strong. [Personality]: Playful and confident.