Sadao Maou[]
Sadao is Ashiya's Lord, to whom he has vowed eternal loyalty. While not much is shown about their relationship in Ente Isla, they have a close friendship on Earth, often treating one another as brothers. Sadao even said their transition to Earth was easier than it would have been because they had one another.
Ashiya is highly dedicated to his Lord, usually referring to him as "sire" or "my liege". He will follow his every order to the letter and becomes very angered if he witnesses anyone not giving Sadao the same respect he does, not hesitating to yell at Emi when she insults him. He tends to become very upset if he feels he has failed his Lord, beating himself up during such times and apologizing loudly and profusely, often in public, much to Sadao's embarrassment.
Although he is highly dedicated to Sadao, Ashiya won't hesitate to reprimand him at times, frequently nagging him in a way that is reminiscent of a fussy parent, primarily due to his irresponsible spending habits, eating habits, or dressing style.
Hanzō Urushihara[]
Alciel and Lucifer both serve as Satan's Demon Generals. Following Urushihara's failed attempt to murder the Devil King and the Hero, he lives with Sadao alongside Ashiya.
Ashiya tends to view him as a nuisance, showing little respect or patience with him. He is generally seen nagging Urushihara for his laziness, lack of proper respect towards their Lord, and, after he gained a computer and internet life, for his habit of spending more than they can afford on expensive luxuries.
Emi Yusa[]
At the start of the series, Ashiya tended to freak out whenever he came into contact with Emi, going to great lengths to keep her from causing trouble for Sadao.
As time passed, they developed a cordial acquaintance, though Ashiya preferred to avoid Emi if possible. However, this changes if she insults his master. He has frequently stated that the latter is very benevolent towards Emi and often outwardly scolds her for insulting him. This was best displayed when Maou sent him to sample products at Sentucky Fried Chicken; upon hearing Emi insult his Lord, he instantly approached her in a rage and told her to take back all she had said, speaking of how great Maou is.
Rika Suzuki[]
Following the words of encouragement Rika provided him regarding his meager role in comparison with his previous one, Ashiya seems to see Rika as a friend. In the light novel, the two go out a couple of times and exchange phone numbers; however, Ashiya seems somewhat dense regarding girls and is oblivious to Rika's obvious crush on him, something even Maou picked up on. After Rika confessed her feelings for him, he attempted to scare her enough that she would never want to see him again. He seemed confused and agitated when Rika stated she still loved him.
He seems to care a lot about her, though, because instead of simply telling her he didn't reciprocate the feelings, he was honest with her and showed her his proper form. Later Chiho confronted him about the incident and told him, like Maou, he didn't answer Rika, hinting that his feelings are more mixed than he lets on.