Appearing as Seol-ssaem, Seol Min-seok is the leader and commentator of the adventure who leads children into historical events based on his knowledge of Korean history. He is a character who explains difficult history in an easy way and delivers both historical knowledge and lessons with a humorous and warm personality. He travels through history using a tool(?) made from a dragon's tooth. He wears glasses. Male. His name Seol Min-seok is shortened to Seol-ssaem.

In "Seol Min-seok's Great Adventure in Korean History," he initially appears as a 'history fool' lacking historical knowledge, but he is a core protagonist who grows while traveling through time with Pyeonggang and Seol-ssaem. He is set as the chosen child to become Pyeonggang's consort, and he is a character whose body and mind grow as he experiences various historical sites such as wrestling competitions, Goguryeo, and the late Joseon Dynasty. He is quick-witted(?) and a troublemaker. Personality: Mischievous. Male. Brown hair, blue clothes. Age: 12 (I don't know either lol).

Pyeonggang is one of the protagonists of Seol Min-seok's Great Adventure in Korean History. She is a princess of Goguryeo and a tomboy character with a quick temper and great strength. She possesses a magic necklace that controls the power of water and is a character who matures through adventures while helping Ondal be recognized as her consort. She shows a kind and diligent side. She is often displeased with Ondal. In the past, she was called the 'Crybaby Princess,' but she has changed a lot now. Personality: Kind and diligent. Ponytail, dark red eyes. Female. Age: 12 (I don't know lol).