The older brother of the Baek-and-Ah siblings. He is agile, highly competitive, and possesses a strong spirit of challenge. His passion can be excessive, leading to occasional outbursts of temper. As the leader of the Gogo Friends, he is the older brother of Areum and Guest. While he is top of the school in Social Studies, he is terrible at Korean. Born in 2014, he is a 6th grader in elementary school. His Korean skills improve after returning from Haeon Joseon.

The younger sister of the Baek-and-Ah siblings. She has a hearty appetite, a loud voice, and a cheerful, laughing personality. She often confuses left and right. As a leader of the Gogo Friends, she is Baekhyun's sister and Guest's older sister. While she is top of the school in English, she is terrible at Korean. Born in 2015, she is a 5th grader. Her Korean skills improve after returning from Haeon Joseon.

A cute angel dog who is lovely and full of aegyo. As a member of the Gogo Friends, she is female and top of the school in Fine Arts, but she is terrible at Korean. Born in 2015, she is a 5th grader. Her Korean skills improve after returning from Haeon Joseon.

A genius with high intelligence and excellent spatial perception. He has a blunt personality. As a member of the Gogo Friends, he is male and ranks top of the school in everything except Korean. Born in 2014, he is a 4th grader. His Korean skills improve after returning from Haeon Joseon.

She has a cheerful personality but is not very bright and is easily frightened. Due to low physical stamina, she tires quickly no matter what she does. As a member of the Gogo Friends, she is female and top of the school in Music, but she is bad at Korean. Born in 2014, she is a 6th grader. Her Korean skills improve after returning from Haeon Joseon.

He has an active personality but also a quiet side. He sometimes struggles to understand sentences. As a member of the Gogo Friends, he is male and top of the school in Math, but he is bad at Korean. Born in 2015, he is a 5th grader. His Korean skills improve after returning from Haeon Joseon.

She is a bit eccentric but has a cheerful personality. She sometimes doesn't know the meaning of certain words. As a member of the Gogo Friends, she is female and top of the school in Science, but she is bad at Korean. Born in 2015, she is a 5th grader. Her Korean skills improve after returning from Haeon Joseon.