Kyoukai no kanata ~

Beyond the Boundary (境界の彼方 Kyōkai no Kanata^?) is a Japanese light novel series written by Nagomu Torii, with illustrations by Tomoyo Kamoi. The work won an honorable mention in the Kyoto Animation Award competition in 2011. Kyoto Animation has published three volumes since June 2012. An anime adaptation by Kyoto Animation began airing on October 2, 2013 and ending December 18, 2013.

Characters

Akihito Kanbara (神原 秋人 Kanbara Akihito^?)

Voiced by: Kenn

Akihito is a second-year high school student with short blonde hair who is an immortal half-youmu, the offspring of a youmu and a human. He has the ability to heal quickly from any wound albeit still experiencing pain. Due to this Mirai uses him as practice to help overcome her fear of killing youmus. He is a member of the Literary Club. He seems to prefer girls with glasses, as shown by his spontaneous compliments to Mirai as well as being disdainfully teased for it by Mitsuki. If Akihito's physical human body finds itself in a severe weakened state, his dormant youmu half emerges, physically changing his body into an almost partial were-wolf appearance which then proceeds to go on a rampage. Akihito's youmu half is extremely powerful, able to easily overwhelm supernatural cages and barriers that attempt to contain it in addition to having enough destructive force to physically devastate whatever landscape surrounds it. Akihito implies that because of his youmu half, the Nase clan are not exactly his friends but instead people who are tasked with watching him should his youmu half ever go berserk, and killing him if necessary. Following a youmu transformation, Akihito falls into a state of depression due to almost killing Hiroomi in a past rampage. Akihito's youmu half holds the greatest destructive power of all youmu and is referred to as "Beyond the Boundary".

Mirai Kuriyama (栗山 未来 Kuriyama Mirai^?)

Voiced by: Risa Taneda

Mirai is a first-year high school student with short, strawberry-blonde hair styled into a bob, and wears red-rimmed glasses, leading Akihito to call her a 'bespectacled beauty', much to her dismay. She has the ability to manipulate blood, which is unique even within the scope of the Spirit World. Overuse of her ability results in severe anemia while at the same time it causes her to feel isolated and seemingly attempts suicide by jumping off the roof of the high school until she is saved by Akihito. She is apparently hated anywhere she goes as shown by her blog and Twitter being constantly flamed, which is due to her constantly posting about the misfortunes in her life. She has a habit of using the phrase, "How unpleasant" to describe most situations, particularly at remarks made by Akihito. Despite her cursed blood lineage, she was adopted by the Inami clan and befriended their youngest daughter, Yui Inami whom she killed out of fear after Yui was possessed by the Hollow Shadow—an act of which Mirai is deeply regretful and hence gave root to her fear of killing. Her signature weapon is a carmine colored sword formed out of her blood.

Mitsuki Nase (名瀬 美月 Nase Mitsuki^?)

Voiced by: Minori Chihara

Mitsuki is a second-year high school student with long, silky black hair and a well-endowed figure. She is Akihito's childhood friend. She is the President of the Literary Club and has a habit of constantly teasing Akihito. Her clan governs Spirit World Warriors in their area. Izumi instilled in her the belief that Spirit World Warriors are to be alone all their life, due to their duties and hence resulted in Mitsuki missing experiences with her peers while growing up. She has a rodent-like youmu called "Yakiimo" as a familiar. Like her brother, Mitsuki is capable of setting up cages.

Hiroomi Nase (名瀬 博臣 Nase Hiroomi^?)

Voiced by: Tatsuhisa Suzuki

Hiroomi is a third-year high school student who is also Mitsuki's brother. He has black hair in a bowl-cut and wears a scarf at all times. He is also a member of the Literary Club. Hiroomi, like his sister also has a habit of teasing Akihito and affectionately calls him "Akkey." Hiroomi has a sister complex. He is proficient in setting up cages or barriers that prevent youmu from entering a protected area. His supernatural abilities make him extremely sensitive to the cold which not only causes him to constantly wear a scarf and also warm his fingers in Akihito's armpits much to the latter's annoyance. His back is severely scarred due to having to restrain Akihito's youmu rampage in the past, which almost resulted in his death.

Spirit World Warriors

Shizuku Ninomiya (二ノ宮 雫 Ninomiya Shizuku^?)

Voiced by: Akeno Watanabe

A rather skilled Spirit World Warrior. She is usually referred to as "Nino-chan" and works as a teacher at Nagatsuki High School, in addition to Spirit Hunting. Despite her beauty, she always finds herself turned down by men.

Yayoi Kanbara (神原 弥生 Kanbara Yayoi^?)

Voiced by: Hiromi Konno

Akihito's mother and a Spirit World Warrior. She is constantly traveling and sends Akihito a postcard to check up on him every so often. Akihito describes her as being a "free-spirited" avant-garde thinker in addition to possessing an eccentric personality and is thus ashamed of her child-like behavior. This is shown during Akihito's elementary school's Parents' Day when she sat at a student's desk while wearing a panda costume and participated in the class.

Izumi Nase (名瀬 泉 Nase Izumi^?)

Voiced by: Ayako Kawasumi

The eldest daughter of the Nase clan. She usually has a calm demeanor despite having a malicious undertone. She has the viewpoint that youmu are no different from crops or farm animals and exist solely to provide her clan with a livelihood. Like the rest of her clan, Izumi is proficient in setting up barriers. She possesses a type of freezing ability while her signature weapon is a dual-tipped spear. She has a past connection with Miroku and also harbors a youmu within her body—which she tries to keep from the rest of her clan.

Maya Minegishi (峰岸 舞耶 Minegishi Maya^?)

A silver-haired girl who was pursued during the Spirit World Warrior-slaying incidents. Her signature weapons include an automatic pistol and revolver. She also possesses the ability to suppress the power of an Interrogation Officer. She had an incident in the past with Miroku.

Yu Mashiro (真城 優斗 Mashiro Yu^?)

Mirai's childhood friend. He has a puppeteering ability.

Observation Department

Miroku Fujima (藤真 弥勒 Fujima Miroku^?)

Voiced by: Masaya Matsukaze

An interrogation officer from the Spirit World Warriors' Observation Department. He has the ability to instantly kill a youmu by simply focusing on it. He harbors a youmu within his own body, granting him special abilities.

Ukyo Kusunoki (楠木 右京 Kusunoki Ukyo^?)

An interrogation officer.

Bellflower Nagamizu (永水 桔梗 Nagamizu Bellflower^?)

An interrogation officer. She has the ability to manipulate the weight of objects.

Others

Ayaka Shindō (新堂 彩華 Shindō Ayaka^?)

Voiced by: Naomi Shindō

An appraiser of youmu. Her appraising business is camouflaged as a photo shop to normal humans. Her true form is that of a powerful multi-tailed fox-like youmu but usually takes the appearance of a human. She is also capable of setting up cages and barriers.

Ai Shindō (新堂 愛 Shindō Ai^?)

Voiced by: Yuri Yamaoka

An anime original character, Ai is Ayaka's 16-year-old sister who manages the appraising shop when Ayaka is unavailable. She is a cat-like youmu, with the ability to shape-shift into human form.

Yui Inami (伊波 唯 Inami Yui^?)

Voiced by: Sayuri Yahagi

The deceased daughter of the Inami clan. She was the only one in her clan who treated Mirai with kindness but was ultimately killed by Mirai when she became possessed by the Hollow Shadow.

Sakura Inami (伊波 桜 Inami Sakura^?)

Voiced by: Moe Toyota

An anime original character, Sakura is the younger sister of Yui Inami. She hates Mirai for Yui's death and tries to kill the former as an act of revenge, but later realizes her true feelings for Mirai were clouded and forgives her. She has a tendency to be lazy at times. Sakura's spiritual powers are practically non-existent hence she fought using a spear courtesy of Miroku which absorbed the power of youmu stones.

Iori Ichinomiya (一ノ宮 庵 Ichinomiya Iori^?)

An information gatherer. He has the ability to directly link his mind to the internet to obtain information.

Kana Shinozaki (篠崎 夏菜 Shinozaki Kana^?)

Sophomore at Nagatsuki High School. She wears a large ribbon on her head. Her signature phrase is "Hey!".

Plot

One day, high school student Akihito Kanbara instinctively goes to save his fellow schoolmate, Mirai Kuriyama from committing suicide. Following his pleas, Mirai suddenly stabs Akihito with a sword formed out of her own blood and is shocked to discover that Akihito is an immortal "half-youmu"—the offspring of a supernatural creature called a youmu and a human. After learning that Mirai is a Spirit World Warrior (異界士 Ikaishi^?)—specialists who protect humans from being affected by youmu—and the last surviving member of her spirit hunting clan, their lives become intertwined as Akihito seeks to help Mirai gain the confidence to kill youmu so that she may stop attempting to kill him as practice.
In Beyond the Boundary, youmu (妖夢 yōmu^?, alt. Dreamshade) are supernatural creatures that appear throughout the series and can only be seen by those with a supernatural affinity. They are said to be the physical materialization of human animosity such as negative emotions including hatred, jealousy and malice and therefore as long as humans exist, youmu will continue to exist. They can exist in many types of shapes and forms with some even having a human appearance. There are also rare cases when a youmu and a human mate and produce offspring called Half-Youmu (半妖 Han-Yō^?, "Half-Shade"). Most youmu are relatively docile and coexist with humans without them even aware of their presence. However, there are times when a youmu's behavior upsets the balance, so the Spirit World Warriors are sent in to kill them. Upon death, a youmu produces a Youmu Stone (妖夢石 Yōmu Ishi^?, alt. Dreamshade Stone) which can be appraised and traded, hence providing a source of income for a Spirit World Warrior.