Arin Kannazuki

Arin Kannazuki is the Trinity Seven of the Ira archive and user of Chaotic Rune magic, whose appearance is strikingly similar to Arata's childhood friend Hijiri. Furthermore, she is also the Magic King's partner, becoming an early ally and later close friend to Arata.

Personality
Arin is quite blase, typically only having a serious or blank expression and rarely showing any other emotions. Because of this, many of her actions and expressions usually do not match. Furthermore, Arin has also often been shown to be blunt and lack a common sense, generally never reacting the same way most people do in many situations. For example, Arin on one occasion chose to bath in the male bathroom because she preferred the quietness. Even when Arata discovered her naked by chance, she barely showed any reactions and acted nonchalant despite his presence. Often times, others have to correct and chide her for her behavior, which she usually finds difficult. However, despite her lack of expression, Arin is not quite a cold as she appears to be. In actuality, she can be kind and caring, even if she does not show that often. Arin gets along very well with her friends, caring for their safety and willing to fight for them. She has also been shown to be perceptive, once immediately noticing Mira's change of attitude toward's Arata.

Notably, after meeting her partner Arata, Arin has changed, showing a wider range of emotions. Prior to his arrival, Arin was solely focused on her research. Since then, others have stated that she has become less emotionless which they enjoy this side of her more. In particular, she has become very devoted towards Arata, even willing to do perverted acts with him. In addition, she is also concerned for his well being, always supporting and protecting him. Her attainment of the Demon Spear Gungir was largely due to her desire to protect him. Since his ascension to Magic King, she has grown more concerned about his state of mind, wishing that he stop fighting to slow his awakening to Astral Trinity. Arin has also shown jealousy when he interacts with other girls; although, she does not mind him being with the Trinity Seven.

Appearance
Arin is a petite, slender young woman with short light blue-gray hair and a single ahoge. Notably, she also bears a striking resemblance to Hijiri Kasuga. However, Arin normally has an emotionless expression, rarely changing her expressions. Although, since meeting with Arata, she has begun to show a wider range of emotions. Her usual outfit consists of her school uniform, a white collared dress shirt worn with a dark blazer jacket with the school emblem, and a plaid mini-skirt. She also sports a red cravat bowtie, black knee-length socks and loafers. On her left ring finger, she wears a simple band ring wtih rune inscriptions that are seen when activating her magic.

Magus Mode: In her magus mode, Arin switches to a dark one piece mini dress under a long sleeved hooded cape with white lace trims and tied with a thin red ribbon in a cravat knot. Her socks and shoes remains the same.

Biography
TBD

Meeting Arata
TBD

Ira - Ruina
Arin's Thema is Ruina from the Ira archive, and her branch of magic is Chaotic Rune, which is based around the ancient writing style Norse runes. Using macros recorded in her grimoire Laguna Yggdrasil, she is able perform a wide variety of spells both offensively and densively. Additionally, her magic is also considered to be one of the more destructive ones out of the Trinity Seven. Upon receiving the Demon Spear Gungir due to her desire to protect Arata, Arin's magic abilities would increase even further, especially her offensive power. She was also able to once break down time and space to teleport herself.

Grimoire

 * Laguna Yggdrasil - Having the appearance of a book, Laguna Yggdrasil is Arin's grimoire which contains macros which she can activate her magic spells. The grimoire takes on the form of a ring on her left hand while dormant

Weapon

 * Demon Spear Gungnir - Due to her desire to protect Arata, Arin is able to summon the Demon Spear Gungnir, which originally belong to Scathach, the founder of Chaotic Rune magic. This spear allows her to nullify magic from the Ira archive and even allow her to break time and space on one ocassion. Also, Gungir is said to be so powerful it can pierce any defense.

Techniques

 * Tiwaz - An offensive spell that shoots magic energy that are capable of destroying a boulder.
 * Sowelu - A light spell.
 * Eihwaz - A defensive spell that is able to ward of shadows
 * Hidden Spell Mistilteinn - Using Gungir, Arin performs a strike that creates a magical blast capable of even destroying Hijiri's strongest defense, Baldr's Blessing.

Relationships
Arata Kasuga - As the partner of the Magic King, Arin cares very deeply for Arata, becoming quite attached to since his arrival. Arin first met Arata in the men's bath unclothed, although she was rather nonchalant during the whole experience. However, because of the nature of their relationship, Arin developed a very interest in him mainly for her research. While on the other hand, Arata was unsure how to interact with her due to her blunt personality and identical appearance to Hijiri. Regardless, the two of them quickly became good friends, even after Arin trapped him or even caused him to create a Breakdown Phenomenon. Arin does not mind Arata's shameless personality, even willing to comply with some of his desires. Likewise, he has also become used to her, appreciating her support and guidance. Although, they sometimes still find aspects of each other surprising and troublesome as well. Notably, since meeting Arata, Arin has slowly begun to change from her usual emotionless behavior, showing more different emotions which has been noticed by her friends. The both of them genuinely care for one another, willing to support and protect each other during dangerous situations. Arin's attainment of the Demon Spear Gungir was largely due to her determination to protect him. Also, Arin can become jealous whenever he interacts with other girls, but is more or less fine with her friends in the Trinity Seven.

Trinity Seven
Lilith Asami - As members of Trinity Seven, Arin and Lilith are good friends and usually get along very well. Although, due to Arin's straightforward character and lack of common sense, Lilith often times has to correct her actions and behavior, which Arin usually finds difficult. Despite this, the two of them care for one another, willing to fight and protect for each other. Furthermore, while Arin is sometimes jealous of Lilith's closeness with Arata, she actually does not mind and both of them continue to remain on friendly terms.

Yui Kurata - Yui and Arin are good friends, both willing to fight and protect one another. When Yui's magic becomes unstable and causes a Breakdown Phenomenon, Arin is one of the people who helps save her. Also, despite the two being interested in Arata, they still remain on friendly terms, although they sometimes get jealous of each other's interactions with him. At one point, Yui has stated that she was willing to be his mistress because Arin was his partner. During battles, both of them are able to work together as a team. During the Magic Research Showdown, they are paired together as a team.

Ish Kerioth
Hijiri Kasuga - Arin and Hijiri have an unknown connection due to their very similar appearances and magic. Both of their Thema's is Ruina from the Ira Archive and they also utilize the same Chaotic Runes magic. However, their personalities are quite different as Hijiri displays more emotions than Arin. Furthermore, as members of Ish Kerioth and Trinity Seven respectively, Hijiri and Arin are enemies. When Hijiri was about to destroy Arata and Lilith, Arin gained the Demon Spear Gungir to break down time and space to save them. Despite the two meeting for the first time, neither of them would comment on their unusual similarities. Notably, Arin's possession of Gungir allows her to nullfiy magic from the Ira Archive, making her a natural opponent to Hijiri.

Trivia

 * As a mage from the Ira Archive, Arin is the opposite of being wraithful, never really becoming angry or showing any other emotionas.
 * Arin's Demon Spear Gungir is named after the Norse god Odin's weapon.
 * Scathach's spear was Gae Bulg, which she gave to the hero Cuchulain.
 * In the initial print of chapter 0, Arin's hair is colored brown in the color spread. However, in volume 1, her hair color has since been changed to her current color, light blue.
 * In the first anime commercial, her bust size is stated to be 83 cm. However, in both episode 1 and chapter 1, she tells Arata her bust size is 82 cm.
 * The anime promotional material puts both Arin's and Yui's bust size at D, even though Arin's manga appearance is much more modest. Arata himself has compared their drastic size difference when both of them slept naked next to him.
 * It is unknown why and how she knows she is the partner of the magic king before meeting, Arata.