Dokkaebis in the novel are hinted from the elf-like being often told in Korean traditional forktale and fairy tales.
So they contain the nature from the original Dokkaebi

Dokkaebi

Dokkaebi is a common word for a type of spirit in Korean folklore or fairy tales.The Dokkaebi is a mythical being that appears in many old Korean folktales. Although usually frightening, it could also represent a humorous, grotesque-looking sprite or goblin. These creatures loved mischief and...

characteristics. very mischievous, likes to play riddles and games, etc.

But the race dokkaebi in the novel also has its originality, like they are able to create and control fire freely, they are extremely afraid of seeing, smelling blood, have good craftmanship, can fly on a giant beetle. In the novel they have their own society and castle built in another dimension.