Arthur is a teen with spiky hair. He originally had a tag around his left leg that allows Eden to track his movements but later destroys this tag during his escape.
As a seraph, his markings are yellow-colored.
Extremely idealistic, Arthur unyieldingly believes in the good of everything and acts on his beliefs, wanting to give all seraphs the freedom he believes they deserve. Having been isolated from his friends after his awakening, Arthur is lonely and as a result wants to befriend as many seraphs as he can.
He is a charismatic leader, knowing how to encourage his teammates and leading them to liberate the other seraphs from the farms. Arthur is also somewhat naive, leading him to do acts without thinking of the consequences such as appearing in broad daylight to attract attention and appear on TV in order to inform other seraphs of his existence in hopes that he would be able to meet them, all without considering that those seraphs might have even tighter restrictions placed on them because of his antics.
Arthur aspires to be a hero and dreams of one day collecting companions with all sorts of powers to form a "Hero Kingdom". After watching Takayama Sou's heroics on the internet, he begins to idolize him and strives to become just like his hero. He aspires to go to Japan to look for him and wants to become his friend.
Due to the circumstances of his parents' death, Arthur believes that he does not live only for himself and sees the world as a wonderful place. Like all seraphs, Arthur is emphatic to his friends' pain and laments his inability to help them as they died.
He has a crush on Robin which is reciprocated.
Before becoming a seraph, he had lived with his father. His mother died of cancer, having chosen to keep him alive instead of treating the disease. Later as a child, their house was burglarized and Arthur witnessed his father's death after the man took a gunshot from a bullet meant for him. Later on, Arthur was converted into a seraph and housed in a farm in Arizona until he awakened as a Bellwether, whereupon he was transferred to the United States under the supervision of his caretaker Biff.
His movements severely restricted and completely isolated from his friends, Arthur became increasingly lonely and bored with his life. He eventually breaks out, saving a little girl who had been held hostage by her own father before quickly returning. He requests to see his friends, as they had not replied the messages he had sent to them, but was rejected.
An unspecified time after his fifteenth birthday, he boldly revealed himself in broad daylight in the streets of New York while transformed. Though he did not answer most of the questions asked by the reporter, he admitted that he appeared on TV in order to inform the rest of the seraphs in the world of his existence, hoping that this act would allow him to meet them. However, he was informed by Biff that his act would have served the opposite purpose and might even put the seraphs at the farms in danger. He was later interviewed by Maria, and noted after the interview that he did not think his actions of appearing on TV were wrong. However, he is reprimanded by Maria, who told him that his desire was only for self-satisfaction. She also informs him that Biff would be replaced by another caretaker for not being strict enough with Arthur, telling him to mature if he does not want to lose even more friends. Though he was not able to apologize to Biff, he was given the game that Biff had ordered for him earlier. A note was slipped inside the case, instructing him to meet at a graveyard if he did not want to forget how it felt to fly. Once there, he discovered a handphone and a battery that connected him to Sky, who asks him if he wanted to change the world with them.
When attempting to save a seraph who had been locked up in a farm, Arthur was caught in an explosion that took away half of his body, only surviving long enough to be washed ashore on Japan's beaches by his wings. His faint voice was picked up upon by Takayama and Karasuma Eishi, although only Takayama reached him in time. There, Arthur revealed all that had transpired and wondered if he had did the right thing by setting his friends free, lamenting his inability to help his friends as they died around him. He died with a smile on his face as he wondered if he could become friends with Takayama, and was later buried at the beach where his body washed up. His makeshift grave is marked by a boulder atop a mound of soil.
Bellwether (先導者（べルウエザー）, Beruuezā): As a bellwether, Arthur is able to control other seraphs. He has his own form of telepathy that is different from the silentwing ability all seraphs can use, and the activation of this power manifests as a giant pair of white wings in the sky.