Lilith Azazel As the first mage (besides Hijiri, whom he didn't know was a mage initially) and member of the Trinity Seven that Arata encounters, Lilith was the person responsible for introducing Arata to the magic world. Initially investigating a Breakdown Phenomenon site, she was surprised to discover the area undestroyed. Investigating further, she discovered Arata as the source and demanded that he give up his grimoire. Refusing, Arata instead convinced her to make him a magician and as a result, enrolled him at the Biblia Academy. Out of the Trinity Seven, Lilith is probably the closest to Arata and interacts with him the most. As his teacher, Lilith tends to act strict towards him on his behavior and actions. Although, she often becomes very flustered by his perverted teasing and antics, causing her to become extremely embarrassed or angry, sometimes even act out violently. Interestingly, Levi once stated that her personality was more of an ice queen before meeting Arata, hinting that he was someone special to her.
However, despite her frustrations, Lilith deeply respects and cares for Arata, willing to support and protect him. Arata, likewise, also feels the same; he considers her and rest of Trinity Seven just as precious to him. It is implied that Lilith is in love with him, often blushing when around him and becoming jealous whenever he interacts with other girls.
Levi was the second member of the Trinity Seven Arata meets upon becoming a mage. Arata first discovers Levi hiding on top the ceiling after he transfers to Biblia Academy. Being just as crafty and perverted as him, she and Arata easily got along with each other. Since their initial meeting, they have become good friends as a result of their similar personalities. Their usual interactions often involve teasing others with perverse jokes and situations. Levi holds great expectations of him, and is always willing to provide support for him, often being the one to explain new things to him. Although, it is unclear whether or not she has feelings for him, she does enjoy being with him and commonly teases him as will, causing him to blush many times. They both care and are willing to fight for each other, becoming concerned when the other is not well. Notably, Levi is also the only member left of the Trinity Seven that Arata has not seen naked, which Arata considers his "final frontier."
Mira Yamana - Arata first saw Mira returning from a mission with Akio upon transferring to Biblia Academy. They would later officially meet when Arin caused him to create a Breakdown Phenomenon. Mira, as head of the Grimoire Security, deemed him as a danger and ordered Akio to destroy him, although her attempt failed due to Yui's intervention. Mira would eventually allow Arata to live after he stopped the Breakdown Phenomenon, but continued to distrust him as she viewed him as an "impure" existence. Since that incident, Mira would maintain her animostity towards him due to his perverted behavior. Despite her treatment, Arata would remain friendly towards her, often teasing her and causing risque situations that sometimes invoked a violent reaction from her. Nevertheless, their relationship would gradually improve when he took the second seat of Grimore Security and embarked on a mission with her to investigate Liber Academy's disappearance. When the both of them became trapped, Mira became unable to use her magic and was forced to rely on his help. Seeing his reliable and good nature, she developed a sense of respect and trust for him. When she was nearly about to killed by llya, Arata, becoming despaired at his lack of power, transformed into Astral Trinity as a result. Astral Trinity would then order her to submit herself to him. However, Mira would reject his offer, stating she had nothing to offer to anyone who wasn't Arata, which helped re-awaken him. Since that mission, Mira's attitude towards Arata has softened, becoming more caring and willing to fight for him. Recently, it has been hinted that she may have developed feelings for him, becoming jealous when he gets close to other girls.
Akio Fudo - After transferring to Biblia Academy, Arata would first catch a glimpse of Akio and Mira returning from a mission. They would not actually meet until Arin caused Arata to create a Breakdown Phenomenon which began destroying the school. Ordered by Mira to destroy him, their first encounter would involve her nearly obliterating him if not thanks to Yui's intervention. Despite their initial meeting, Akio and Arata remain friendly and get along very well due to their laid back natures. Akio does not mind Arata's perverted nature and usually plays along with his antics. However, she will usually become embarrassed when he accidentally strips her with his magic. Nevertheless, she is willing to support and fight for him. After Lieselotte first steals his magic, Akio allowed him to copy hers, personally teaching him her magic. During their Sky Library mission, they grow closer after Akio reveals her past to him, telling him about the destruction of her hometown. This helps motivate him to defeat Abyss Trinity, the one who destroyed her village. Akio becomes grateful for his actions, thanking him for allowing her mother and hometown inhabitants to rest in peace. Since that mission, Akio has started to call him "big brother" and her "beloved." Akio has once stated that it was fun being with him. It is also hinted that she may have developed feelings for him.
Arin Kannazuki - Arin first met Arata when he discovered her taking a bath in the boys washroom. Proclaimed as Arata's partner (or wife), Arin develops in interest in him early on to see if he was worthy of becoming her partner. As a result, she had once trapped him to test him and even caused him to create a Breakdown Phenomenon. Despite this, Arata does not hold her actions against her and still treats her normally. However, he initially was not sure how to act around her because of her identical resemblance to Hijiri. Nevertheless, they eventually become very close over time. Arin has since become very attached to Arata, becoming jealous whenever he interacts with other girls. She especially does not like him meeting other girls other than the Trinity Seven, stating they were alright because they were friends. They care very much for each other, willing to support and fight for one another. On one occasion, Arin broke down time and space to save Arata when he was nearly about to be killed by Hijiri. Since Arata became a Magic King, Arin has become increasing concerned about his well-being, as he could potentially re-awaken as Astral Trinity. Regardless, she decides to continue to aid him. Since meeting with Arata, others have stated that she has changed, focusing less on her studies and showing a wider range of emotions. In chapter 56 she declared that she is in love with Arata.
Yui Kurata - Arata first encountered Yui when she dragged him to her dream world to save him from being annihilated by Akio. In her dream world, he would first meet her idealized self. Thankful for her intervention, they would get along almost immediately; Yui would even start calling him big brother straightaway. Due to him creating a Breakdown Phenomenon, she would help him learn to control it by inspiring him to find his Thema and Archive. However, some time later, she would also end up creating her own Breakdown Phenomenon due to interactions with Arata which caused her magic to become unstable. Feeling responsible, Arata would help save her and finally meet her true physical appearance, quite literally as she was naked. Grateful for his help, Yui has since become very attached to him, often hugging him as much as possible and even going into his bed bare naked. She does not mind his perverted behavior and plays along with his antics. She can get jealous and nervous whenever he interacts with other girls. Out of the Trinity Seven, she is probably the most open to his suggestions, stating that she will be the one to do everything with him. However, despite her willingness, Arata surprisingly holds himself back; once refusing a kiss from her, stating that that was something for when they were closer. Nevertheless, they have a very close bond, willing to support and protect one another.
Lieselotte Sherlock - As the last member of the Trinity Seven Arata meets, Lieselotte originally was missing before Arata transferred to Biblia Academy. She would suddenly reappear in front of him and the rest of the Trinity Seven, including her sister Selina, as an evil mage. Despite being an enemy, the two of them initially acted very friendly with each other, due to their similar perverted and laid back behavior, as well as their dislike of work. Although, Arata would disagree with her choice of stealing friends' magic. Nevertheless, Lieselotte took an immediately liking to him, finding him interesting and amusing. She also does not mind his perverted behavior, even playfully offering her own suggestive actions. However, she would end up stealing his magic, offering information on Hijiri if he joined her side to lower his guard. Later on, he would recover his magic by learning Akio's Mantra Enchant and eventually defeat her. Regardless of her actions, he would still attempt to comfort, asking her to return with him to their friends. Unfortunately, her use of her Final Technique trapped her in her own time dimension. Promising to save her, he would become determined to master her magic, Logos Arts, to bring her back. During Ish Kerioth's attack on Biblia Academy, she would be able to return thanks to her sister Selina lending her body. When prompted by Hijiri to choose a side, Arata's appearance would ultimately cause her to side with him and the Trinity Seven. Since then, the both of them have grown very close, strongly trusting in one another despite their past. During the Sky Library mission, Lieselotte would help prevent Arata from turning into Astral Trinity as well as teach him to master her magic so he could control Judecca. Believing that he didn't trust her, she was surprised when he allowed her to steal part of his magic, proclaiming that she was his friend no matter who she was and that he liked all sides of her. Hereafter, he would master the Logos Art with her help and bring her back to the real world. After that moment, Lieselotte has since become very grateful to Arata for saving her, caring deeply for him and getting jealous whenever he interacts with other girls. They are both willing to support and protect each other from danger. Out of all the Trinity Seven, they have kissed the most times.
Sora - The Astil Manuscript or Sora, was originally Hijiri's grimoire before being given to Arata. When a Breakdown Phenomenon was destroying their town, Hijiri would give the grimoire to Arata, asking her to protect him and grant his wish before disappearing. Despaired, Arata would then demand Sora to bring back his normal days. Complying with his wish, the grimoire would recreate the world in a different dimension and pose as Hijiri until Lilith's arrival. When Arata, whom had forgotten about the ordeal, began to become suspicious, she attempted to dissuade him from the truth by offering to follow his desires. However, he would figure out her deception using an old picture the real Hijiri drew as a child, much to her amusement. With the truth revealed, Sora would then return the area to it's destroyed state, as well as reveal that Hijiri was still alive. This information would immediately turn out to be the catalyst for Arata's decision to save Hijiri by becoming a mage. Following his transfer to Biblia Academy, Arata and Sora have gotten along very well due to their similar easygoing and perverted nature, often teasing and playing off with one another. Sora, in particular, enjoys her master's open personality, occasionally helping into evocative situations. Furthermore, she is very loyal towards him, willing to support and protect him no matter the circumstances, saving him from most dangerous situations. During battles, they have been shown to have great teamwork, understanding and trusting one another's intentions. Despite Arata's short time as a mage, his abilities has progressed greatly partly due to her magic and guidance. Initially, Sora would remain in her grimore book form, always remaining by Arata's side. During Lieselotte's return, she first started appearing in her human form, while also revealing her current name given by Hijiri. Currently, she now uses this form to interact with him regularly, sometimes offering to something suggestive with him. Since forming a contract, the two of them have become very close, deeply caring for one another's well being. Despite her not being human, Arata does not treat her like a tool, worrying for her safety when she is in danger. Sora's imprisonment by Illya during the Liber Academy mission was one of the reasons that caused Arata to transform into Astral Trinity. However, Sora would eventually force him back to normal, stating that she perferred her idiotic master more.
Ilia - Like Sora, Ilya or the Ilias Fragment, was originally Hijiri's grimoire before joining Arata. Ilya cares deeply for Arata, being quite protective of him and getting jealous whenever he interacts with others girls. Before he discovered magic, Hijiri would often have to leave for magus business. During those times, Ilya would often pose as her and take care of Arata, unbeknownst to him. He would not find out until they would meet again when he became trapped inside her alternate dimension while investigating the disappearance of Lieber Academy. Taking on HIjiri's form again, she would reappear before him, acting cheerfully and casually with each other despite being enemies. Although, she would become jealous whenever he showed concern for other girls, namely Mira. Under Hijiri's orders, she would attempt to convince Arata to stay with her until Hijiri destroyed the world, offering herself to satisfy any of his desires. While tempted, he would ultimately refuse, causing her to forcefully restrain him. However, when she was about to kill Mira and Sora, this would cause him to turn into Astral Trinity, much to her horror and helplessness. As Astral, he would force her into her true human form, terrifying her greatly. Eventually, he would be return to normal due to Sora and Mira's efforts. Despite her actions, Arata would not hold a grudge against her, thanking her for taking care of him and asking her to join him, which she happily agreed. Since then, the two of them have grown closer together, trusting and supporting for one another. Although she is sometimes bothered by her master's nonchalant and perverted personality, Ilya is grateful that Arata sincerely cares for her and continues to follow him.
Lilim - Upon absorbing his magic, Hermes Apocrypha is able to become sentient, thus viewing him the Demon Lord Candidate as her father figure. Despite his surprise, Arata would nevertheless quickly come to accept the grimoire as his daughter, even giving her the name of Lilim. Forming a strong parental bond in spite the short duration of their relationship, he in particular would become grateful of her presence, allowing his friends to bond with one another. Futhermore, the two are willing to work together to protect against a common enemy. However, because Lilim possesses his magic, Arata can utilize her to replenish himself at the cost of Lilim reverting to her original state. Nontheless Lilim is willing to sacrifice herself to protect those she cares for, prompting them to promise to reunite in the future.
Okto - Arata would initially meet Okto after incapiacitating the demon army she summoned to evaluate his strength. Although the grimoire was hesitant due to her actions, Arata nevertheless quickly forgave Okto, even requesting her opinion of his skills which she readily gives her approval. Furthermore, the Demon Lord Candidate would promise to help Okto rescue her remaining sisters across Dante's Gate.
- Main article: Black Imperial Sword Judecca#Relationships
Upon forming a contract with Judecca during the Sky Library mission, Arata became the Demon Lord Weapon's master, gaining the ability to wield and utilize her abilities. Furthermore, since switching to the Sword Magus class, the two quickly developed a strong bond, being able to efficiently coordinate during skirmishes as well as intimately support each other between battles.
Red Imperial Sword Caina - Red Imperial Sword Caina is owned by Abyss Trinity and Arata had battled Abyss, who used the weapon. However, later on, Abyss Trinity fused with the sword and visited Arata and Lilith right before Lilith's battle started in the Magic Tournament. Abyss lent Arata the sword when Arata tried to save Anna and Arata managed to control the sword well along with Judecca.
Ceres - Though the both of them never really met, but Arata did have a similar feeling of her when she saw her in a dream. Arata seems to have met her but a bigger version of her. The real Ceres was extinguished during the Great Tsushima War and regenerated with the current Hijiri and Arin, she also regenerated her body and soul to seal the power of the Great Demon King, which when at the time Arata copied his consciousness and memories. She helps Arata whenever he uses his Demon eukaryotic power with her voice. She was happy to see him again in his dream. She was worried about him if he would fight Hijiri and lose her forever as well. Later in the real world Ceres appears in front of Arata while he was depressed at Hijri's loss, and mentions that Arata and her soul are one now, and will always be together. He thanks her with a smile for saving him from his despair. Ceres also seems to love and care for Arata as she always smile when they are together and even hugged him once.
- Main article: Hijiri Kasuga#Family
Arata and Hijrii were living a relatively normal life as cousins until a Breakdown Phenomenon suddenly occurred in their hometown. Hijiri, a secret mage, sacrificed herself in order to protect Arata, which would later motivate him to become a magus as well in order to rescue her. Possessing a close and understanding bond, the two continue to remain cordial and care for one another even after reuniting as adversaries.
Lugh - As a member of Ish Kerioth, Lugh and Arata are inherently enemies. However, despite their affiliations, this has not stopped them from getting along and working together. Arata first met Lugh during Ish Kerioth's attack on Biblia Academy where he accidentally fell on top of her and touched her breast, much to her embarrassment. Almost immediately after, he would ignore the incident and continue to act normally, surprising her of his perverted and nonchalant nature. She was also under the impression that he attempted to make her his mistress. Since their initial encounter, the two of them have generally gotten along very well. Arata rarely treats her as an adversary, with the few exceptions when she tries to betray him. Even then, he does not hold her actions against her, typically jesting with her in the end. Similarly, Lugh truly does not hate him; she is merely wary of his status as a Magic King Candidate. After actually interacting with him, she has since gradually warmed up to his character, although she is still faithful to her mission. During the Sky Library investigation, Lugh, who was captured, would join his group in the inspection, much to Arata's disbelief. When the trip goes wrong, he begins to rely on her, slowly trusting her despite some uneasy moments. Upon Abyss Trinity's appearance, she chooses to support and protect him than escape, even showing concern for his safety. Ironically, after Arata masters Judecca, she quickly desires the weapon which immediately drains her magic in an erotic manner when she touches it. As a result, she states that she will marry him because as his wife she will get his possessions. During the final battle with Abyss Trinity, she would help disarm his weapon, expressing that it was her nature to take all the good things for her husband.
Royal Biblia Academy
Selina Sherlock - Selina is one of Arata's classmates and good friend in Royal BIlbia Academy. Upon transferring to Biblia, she was one of first few people he meets, accidentally bumping into him while announcing his arrival as a Magic King Candidate. Afterwards, Selina would initially interact with him to get a scoop for her news article, however they quickly got along with each other, being able to easily talk to one another. But while they do enjoy each other's company, she is also occasionally shocked and embarrassed by his perverted habits, sometimes having to be the voice of reason. Regardless, Selina found him to be interesting due to his magic abilities and relationship with the Trinity Seven. After Arata helps rescue Yui, she even begins to hope that him can save her sister Lieselotte. During Lieselotte's return, Selina helps save Arata avoid her sister's attack. When Lieselotte eventually steals her magic and her life becomes in danger, he showed great concern for her safety and became motivated to stop Lieselotte. Later on, they would work together to liberate Lieselotte from her frozen world. Overall, they care for one another as friends, willing to support and fight for each other.
Royal Akasha Academy
Anastasia-L - Arata first encountered Anastasia, or Anna, when he passed by her during the Biblia Academy school festival. Almost instantly, he became aware of her presence, blushing when he tried to approach her. However, he was unable to talk to her when Mira and Lilith chastised him for looking at other girls. They would not formally meet until later when Anna helped him after he fainted from a hallucination. Despite interacting for the first time, the two of them immediately become friendly with one another; they even start calling each other by their personal names. Arata is very conscious of Anna, almost always becoming embarrassed in her presence, especially whenever she gets close to him. Whether or not this is romantic or even genuine remains to be seen. Likewise, Anna also seems to enjoy being with him, usually flirting with him whenever they meet. However, later revealed to be the Saint of Resurrection, she may also see him as an adversary, calling him her "worst enemy" despite blushing greatly after first speaking with him. Notably, Arata's apparent attraction to Anna has caused some jealousy from the other girls.
Ayesha - Due to her support of Anna's goals, Ayesha and Arata are technically enemies despite their lack of interactions. However, the two would later become allies after he fell under Anna's control. During Ayesha's battle with Mira, Arata would intervene and save her from defeat, although Ayesha insisted that she did not require help. Nevertheless, Arata would charm her after agreeing, causing her to blush greatly.
Radix Astil - After surrendering his Demon Lord Element, Arata was no longer considered by Radix as a suitable master for her "daughter", Sora. As such, the grimoire desires to retrieve her copy, regardless of Arata's will and more than ready to eliminate him should he becomes an obstacle to her master's goal. But for the meantime, she has been content on allowing them to remain together temporarily, although she intends to appraise his abilities. However, her methods in setting her trials have angered Arata, once causing him to use his magic to overwhelm her much to the grimoire's surprise. After being rescued by Arata, Radix may have developed feelings for him.
- Main article: Rubine/Relationships
Rubine - Despite being on opposing sides, Arata and Rubine normally behave in an amiable manner towards one another while coming into conflict on occasion.
Aries Cardia - Although forgotten about her, due to timeline difference, Aries does still remember and calls him the same instead of his real name, using 'devilish demon lord'. Upon their first meeting she cried, proving she still has great feelings for him. Aries later introduces herself as the Arbitrator of time to him, and even said that she will protect him this time. Aries has great trust in Arata, when Selina was struggling against studying magic and Thema's, he helped her, to which Aries is grateful for. Later after the Goddess of Darkness revival, Aries has requested from him to help her fellow friend Faunaria. Arata has apologized to her for not being able to see her best friend Lieselotte. Aries wishes to support Arata at any situation, unlike the rest of the Arbitrators.
Aryan Celestial - The Goddess of Darkness, whom Arata has great connection with her, and is partially the revival of her. Aryan at first was Ceres's host, and has tricked him at first using a façade replicating Ceres's emotions to him, which at first he believed, until later he found that she is the goddess but in Ceres's body. Despite that, at the World of the Black Emperor, he did care for her due to her being in Ceres's body. When she was feeling pain because her connection of Giant Nornil Pillars loss, Arata has shown a worried expression. Even though she is his mortal enemy, Aryan has shown a very great interest in Arata, prior to their departing from the world, she told him her name, and the both made a promise to each other in the final battle, if she wins the world is finished and everything will be one with her, in his case he will rule the goddess herself. Aryan later upon her revival in the final battle, has only shown her interest in Arata, wanting him to show him what despair feels like. She makes him watch as she defeats all the Arbitrators, and wonders if he is watching with happiness. Also to make sure he witness her actions, she creates a screen made of crystals. Afterwards when they both confront each other, remembering their promise they start their battle, only for Aryan to kill him by his own sword, stabbing him in the abdomen, she smiles in delight and pleasure.