Yami Himura/Family/Friends

Tōka Himura
Tōka Himura is Yami's older half-sister, the two of them sharing a father. Due to her distant dad, at the age of 17 she was the one who raised Yami and Riku using the money her dad would send her to take care of the three of them. She is shown to be angry, aggressive, and annoyed with Yami's trouble making and criminal behavior repeatedly telling him to put a end to it and to focus on school. Unknown to Yami, she actually knows that he became a devil, confronting Aurora and telling her to keep Yami out of trouble. It is unknown how she knows Yami is a devil but it is revealed to Ex and Aurora that she has strength above what a normal human possesses. She works as a news-reporter in Tokyo.

Riku Himura
Riku is Yami's older half-brother, being seven years older than Yami. He shares the same father but a different mother to Tōka and Yami. He is shown to dislike his mother who was downright abusive towards him which caused him to run away to live with Tōka and his father. His father left, a few days before Yami was born and only came back to give Yami before leaving for 17 years. This caused him to develop a distant relationship with his father. Riku repeatedly shows annoyance at Yami's behavior similar to his sister, he repeatedly tells Yami to grow up and focus on his studies or to get a job. Despite this, he shows amazement at his brother's intelligence. Unknown to Yami, Riku also knows of the supernatural, when he learns that Yami is a devil under the Lucifer girl he sighs in disfavor stating "it was bound to happen", it is unknown the meaning of those words. He possesses the same strength as his sister and he works as a police officer in Tokyo.

Yata Misaki
Yami's best friend since childhood, the two are considered partners in crime with both being involved in drug selling and street criminals. Unlike Yami however, Yata enjoys playing the guitar and is always seen with his skateboard. Unlike Yami however who is simply cold towards others, Yata is boisterous, rude and prideful young man. He is very brash and brutal, showing no hesitation to get into a fight, as well as vulgar and irritable. He is insecure about his height and curses openly towards people when things don't go as he'd planned or when people make fun of him. He once beat up a gang leader with his baseball bat because the guy called him "little man", which Yata assumed he was simply referring to his height and not because of his age. He is sixteen years old, making him one year younger than Yami. It is revealed that he has no parents, instead living by himself in a apartment.

Sophia Yuzaki
Sophia is a half Japanese/half British girl, and is the second of Yami's two childhood friends. She is the complete contrast to Yami and Yata, instead of being cold or loud mouth and rude, she is a cheery and bubbly young girl which causes people to question why she spends her time, hanging out with them. She used to go to Silver Star Academy with Yami, after being told by the teachers and administration to stop being friends with Yami because he was holding her back, she refused so as retaliation they start unfairly abusing Yami with the student council even joining in to try to get Yami to resign from the school. Sophia finally convinced Yami to and they both transferred over to Shitori Academy with Yata. It is revealed by Yami that she has a perverted side that she only reveals with him and Yata. She tried to date Yami at one point but the two didn't want to ruin their friendship if things ended badly so they categorize themselves as "friends with benefits". She shows a slight sting of jealously when Yami is transferred to class 4-C. She is the only one who knows why Yami carries a distrust of girls he is in relationships with, with her being the only girl Yami is actually close to and feels he can relate to.

Trivia
Tōka is based off of Tōka from Chuunibyou and she shares a lot of similarities (including her name) with her counterpart.

Two characters (Yata and Riku) are based off of K project characters. Yata shares the same personality and appearance as he did in K Project.

Sophia is based off of Anna Nishikinomiya from Shimoneta.