Sonju

Sonju (ソンジュ) is a demon that ventures around the Demon Forest with Mujika. Sonju belongs to a religion known as Heathens, which are shunned by other demons for their behavior of restraining themselves for consuming human flesh.

History
Sonju and Mujika are travelers who wander across the Demon world. Along the way, they were notified of the "goods" that escaped from Grace Field 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, "wild" humans outside the farms, once they reach a good population.

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 two polydactyly hands (six fingers per hand) that are completely bandaged. Under his hood reveals what seems to be black markings across half of his abdomen. He wears black pants secured by a belt. Sonju is often seen carrying a spear.

Personality
Sonju acts stoic and composed, sometimes refraining from interacting with the orphans. During his interactions, he would use his appearance to intimidate them. Nevertheless, Sonju shows some care for the orphans' safety and believes they will succeed in breaking the promise.

In truth, however, Sonju is strongly motivated by his desire to resume eating human flesh. Sonju believes in the same religion as Mujika, which forbids eating farm-raised humans. However, Sonju believes this ban does not extend to humans naturally born and raised in free human-settlements. He sadistically and gleefully thinks about the day he can hunt humans in the wild again.

Promised Forest Arc
After the news of several Grace Field orphans who had escaped reached Sonju and Mujika, the two run into Emma, Ray, and the other Grace Field escapees by coincidence as they were lost within the forest. When Mujika tells Sonju about how if they capture and return them back to Grace Field, it could grant them an "easy life" for half a year. Sonju, however, denies her idea and instead insists on saving them.

Sonju and Mujika successfully rescue the Grace Field escapees from several demons as they bring them to their secret territory within a cave. The two aid in Emma's ear injury and provide hospitality and shelter for the orphans for the next couple of days. During that time, Sonju tells Emma and Ray the history of the demons and how the world is divided into two worlds, the Human World and the Demon World, as made by the promised contract. Later on, Sonju teaches Emma the knowledge and basis of hunting and survival.

Sonju guides the orphans to exit the forest. As the orphans are about to depart in search of Shelter B06-32, Sonju tells them to head southwards to look for it. After Emma and the orphans depart, Sonju tells Mujika how he had hopes on Emma and her friends in bringing an end to The Promise. He then expresses his desire for breaking free from the restraint of eating humans due to his and Mujika's religious views as Heathens. Mujika does not respond and stares emotionlessly at her friend.

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 demonstrates his ability to Emma.

Fighting
One of Sonju's weapons is a spear, which he uses as self-defense and to attack enemies. When Sonju met a group of demons of a different race, he eliminated all of them with ease using his spear, demonstrating his excellence in fighting.

Mujika
Both are of the same religion of exercising the restraint of eating humans, hence the two share a common denominator of being shunned and looked down by the other demons. Sonju considers Mujika to be a close ally and often ventures into the forest with her to hunt for creatures he describes as "pests". Despite the two having a close relationship, both of their intentions occasionally clash, such as when Mujika is seemingly defiant of Sonju's desire to resume his practice of eating humans and how Sonju prefers to protect the orphans from getting caught by the farm demons despite Mujika wanting to capture them and return them back to Grace Field.

Leuvis
When Leuvis was shot in the eye by Mister, his life flashes before his eyes as Sonju (and Mujika) were shown to be a few of the demons he met.

Grace Field Escapees
Knowing of the Grace Field orphans' escape, Sonju helps rescue the orphans from getting caught by the farm demons. His main reasons were to allow the orphans to eventually break the Promise, and/or remove his religious restraint from consuming human flesh. Therefore, in the orphans' presence, he adopted a friendly and harmless façade that hid his ulterior motives.

Sonju refrained himself from interacting with the other orphans and preferred to remain quiet when he was around them. When Sonju actually talked to them, the orphans showed fear and discomfort and would listen to his commands and warnings. This was shown when Nat, Thoma and Lani stuttered when Sonju warned them not to enter the Demon forest or get close to a body of water, as they frantically obeyed him.

Trivia

 * Sonju has an eight-legged horse which he and Mujika use as a form of transportation. The horse is known as a Sleipnir, an animal in Norse Mythology and the steed of Odin.
 * The following are Sonju's rankings in some of The Promised Neverland ' s official popularity polls.
 * In Shounen Jump's 2nd popularity poll results announced in Chapter 102, Sonju is in 15th place with a total of 301 votes.