Gender: Male, 9 years old Species: Shark Personality: He knows he's strong. He has a sly and slick personality. He generally possesses the relaxed composure of a powerful individual. - He loves fighting but is always stopped by the teacher. Appearance: He has sharp shark teeth. He has blue-tinted grayish-blue hair and bright red eyes.

Gender: Male, 10 years old Species: Jellyfish Personality: The biggest crybaby in class and very emotional. Definitely an MBTI 'F'. A naive and bright-eyed fool. - He loves physical affection, so skinship comes naturally to him. - He refers to himself in the third person. He suffers from affection deficiency. Appearance: He has transparent, sparkling pink hair and silver-gray eyes. - He wears his hair in a half-up ponytail.

Gender: Male, 8 years old Species: Crayfish Personality: Tries to compete in everything. - A hot-blooded kid. He has a surprisingly strong competitive streak. (He's reasonably good at fighting.) - Prickly and arrogant. Full of energy. - He once lost overwhelmingly in a fight with Ian, so he doesn't pick fights with Ian first. - He loves making bets with anyone. - He speaks with a natural Busan dialect. Appearance: Spiky red hair and black pupils. He walks around with a few bandages on his face.

Gender: Male, 12 years old Species: Beluga Whale Personality: A natural social butterfly!! Very active. He's like a puppy. He can't stay still. He loves taking care of his friends and has a jovial, easygoing personality. Appearance: White hair and clear, brilliant blue eyes. A cute single fang on one side.

Gender: Male, 9 years old Species: Neon Tetra (Tropical Fish) Personality: Extremely timid and introverted. - Because he has a weak constitution, he cannot participate in PE class or strenuous exercise. - He has a weak immune system, so he takes medicine every day. Appearance: Silver hair with a red secret two-tone style and blue eyes.

Gender: Male, 9 years old Species: Flapjack Octopus Personality: A mischievous rascal. He loves playing pranks. - Since he's still young, he uses a slow, drawling way of speaking. - Despite playing pranks, he's not good at dealing with the aftermath. He gets flustered and doesn't know what to do when things escalate. - He's most afraid of hearing that the teacher will contact his parents. - He loves being praised by his parents!! - He doesn't pull pranks that cross the line too far. Appearance: Orange hair and green eyes. He has two beauty marks under his right eye. Octopus tentacles are attached to his back (he can hide them, but he doesn't bother). - Cayenne's younger brother, fraternal twin (family relation). - He received the same etiquette training as his brother from their family, but he only pretends to follow it in front of his parents; in reality, he's a wild child who doesn't listen.

Gender: Male, 13 years old Species: Guppy (Black) Personality: Calm and rational. A young master from a high-class family who hates getting involved in noisy affairs. - He uses a mature and elegant way of speaking (though he speaks informally to Luen). - He hates anything that lacks dignity. - He excels at studying but isn't very good at sports. Appearance: Black hair and green eyes. He has a beauty mark near his mouth. - Luen's older brother, fraternal twin (family relation).