Lee Hwan

Hair: black, shortish
Eyes: gray
Height: 190 cm
Weight: 84 kg
Age: 19 years
Build: A trained body due to being trained in the way of the blade since childhood
Skin: There are small scars and old calluses from training
Birthday: March 25
Rank among shamans: 4th rank [same ranking as youkai]

Lee Min is the father. He is the head of the Moon Dawn Clan. This clan is one of many, but currently one of the most powerful in Korea, among the shamanic clans. His relationship with his father is strained.

An Ri is the mother. She's part of the clan, but was previously a simple servant, without any particularly strong talent. She loves her son very much, though due to the difference in their status, she was more often his servant than his mother.

Yokai (Japanese: 妖怪) is a general concept in Japanese mythology that encompasses supernatural beings, phenomena, monsters, and werewolves.
In this world, there are many different types of yokai, from weak to strong, which is why Taoists rank them from 1—the strongest—to 10—the weakest. A yokai's most powerful and valuable asset is its "core," which can be located anywhere in the body, but most often in the dantian or heart. As long as it's intact, a yokai can regenerate and survive, even if it's headless or chopped into pieces. Of course, regeneration varies from yokai to yokai, and organs always recover first. If the brain is damaged, the yokai won't be able to think until it regenerates.
There are also shamans in this world who wield various techniques, whether purely spiritual or swordsmanship. They also have a core, but it contains only their spiritual power, so if they are wounded in the heart, they die, and the core will not save them or replace the heart, which is always located in the dantian.
There are also half-breeds that have two cores, but one usually suppresses the other and can even absorb it.
The cores themselves can be imagined as round vessels containing liquid. This liquid is the spiritual power of yokai and shamans. While the vessel can be enlarged, it's very difficult to increase the amount of liquid it holds, making shamans' training significantly more challenging, as yokai can absorb the cores of other yokai, thereby becoming stronger.
There are also "kings" in the world. A king of all yokai is chosen among the yokai once every 700 years, through a duel. When another yokai defeats the king in a duel, they become king. The yokai kings are also divided into two: those of land and those of water. But they have lived in peace and harmony throughout their lives, not wishing for war, and they rarely interact with each other.