A handsome man who wears glasses and possesses vast historical knowledge. He is kind and gentle, but he gets frustrated whenever Ondal doesn't listen. He addresses Pyeonggang as "Princess." Since Ondal is Pyeonggang's consort, he tries to help their relationship. He is a great scholar from Goguryeo who works as a researcher in the modern era. He carries a piece of chalk called the "Dragon's Tooth," which allows him to time travel to the past. He plays the role of teaching history to Ondal. 20 years old.

A beautiful girl who is kind yet bold and confident. She has strong pride and can be a bit prickly. She really, really, really likes her consort, Ondal. She came to the modern era with Master Seol to make Ondal her consort. 12 years old.

A handsome boy who is kind, quirky, and a bit of a fool. He is Pyeonggang's consort. He has a massive appetite. He travels through history together with Master Seol and Pyeonggang. 12 years old.

A kind man who is Pyeonggang's grandfather. He is a researcher and the head of the institute where Master Seol works. He is very knowledgeable about history and loves coffee. He refers to Master Seol as Dr. Seol.

Master Seol's cute pet dog. More than just a pet, he plays a supporting role in the adventures, providing big laughs and comfort to the companions.

A man with average looks who is a villain. He tries to manipulate time to make himself the greatest person in history, constantly interfering with Master Seol's group. However, he always fails, which usually ends up benefiting Master Seol and his friends.