Sonju

Sonju (or Sung-Joo) is a demon that lives outside Grace Field House. He saved Ray just before he was captured by his demon-hound pursuers. He and Mujika were suspected to be demons by Ray.

Appearance
Sonju is a relatively tall and lean demon. He wears a hood and a mask that covers his entire face which when taken off, reveals his abnormally sharp canines. He has a horn at the center of his forehead and polydactyly, with six fingers on each hand, which are entirely wrapped with a bandage. Under his hood reveals what seems to be black markings across half of his abdomen, and black pants which is secured with a belt.undefined Sonju is often seen carrying a spear.

Personality
Sonju believes in the same religion as Mujika, hence is strongly against the practice of eating humans. However, Sonju remained reluctant and was eager to resume his intention of eating humans once their population increased. Sonju retains a stoic and composed personality, as he sometimes refrained himself from interacting with the orphans, and during the times when he does, he was known to intimidate them due to his appearance. Nevertheless, Sonju on a certain degree still care for the orphans' safety and have faith in them being able to break the promise.undefined However, what he doesn't tell the children is that his religion does not forbid him and Musica from eating all humans, but humans born in the farms. As such, he has a hint of sadistic glee in him when he thinks about the day he can hunt humans in the wild again.

History
Musica and Sonju were travelers who wander across the Demon world, along the way they were notified of the "goods" that escaped from Gracefield House. Sonju refused to take the children back to the orphanage, as he wanted the children to be free so that he can hunt their descendants once they reach a good population and he can start hunting "wild" humans outside the farms again.

Promised Forest Arc
He tells Emma and Ray that the world is divided into two, the Human World and the Demon World as made by the promised contract.

Archery
Sonju has proven himself to be an expert at archery. Being highly skilled, he was able to precisely hit targets from great distances, such as shooting down a bird in the sky when he tried to demonstrate his skill in archery to Emma.undefined

He is skilled enough to kill Demons.

Mujika
Both are of the same religion of exercising the restraint of eating humans. Sonju considered Mujika to be a close ally, and often venture into the forest with her to hunt for creatures he described as "pests"undefined. Despite the two having a close relationship, Mujika is defiant of Sonju's intention of resuming his practice of eating humans.