The Bear Spirit Hakja is the feature of many stories from the Era of Unbound Spirits, along with their partner, Man-Wol. In particular, they are known as a doctor, scholar, and researcher, traveling the whole of Goguryeo looking for new plants and so their uses can be discerned.
Scholars debate whether or not Hakja was truly their name as it is also a word meaning scholar and could have been a title for them instead.