Left to right: Mitsuki, Mirai, Hiroomi, and Akihito.
Kyoukai no Kanata (also known as Kyōkai no Kanata, English title Beyond the Boundary) is a Japanese light novel series by Nagomu Torii, with art by Tomoyo Kamoi. The light novel was published in June 2012 by Kyoto Animation as part of the prize for winningnote technically an honorable mention as they couldn't decide on a single winner that year, so each member of the four-way tie was published and the cash prize was equally split amongst them a writing contest they held. The novel was adapted into an anime, also by Kyoto Ani, for the fall 2013 Anime Season.The story follows a high school junior named Akihito Kanbara. Although the boy appears human, he is half yōmu and invulnerable to wounds because he can heal quickly. One day, Akihito meets freshman Mirai Kuriyama when it seems she is about to jump from the school rooftop. Mirai is isolated because of her ability to manipulate blood, which is unique even among members of the spirit world. Disturbing events begin to unfold after Akihito saves Mirai.The first trailer for the anime was released May 24, 2012 on Youtube. The anime adaptation started on October 2, 2013 as part of the Fall 2013 Anime season. Kyoto Animation is producing the series and it is directed by Taichi Ishidate (marking his official directorial debut, having served as co-director on Nichijou), with script supervision by Jukki Hanada and character designs by Miku Kadowaki.
Always a Bigger Fish: Thought the Hollow Shadow was scary? Apparently there are similar youmu out there whose power levels are leagues above it.
Taken to the logical extreme with Beyond The Boundary, the most powerful youmu in history.
Amazingly Embarrassing Parents: Akihito's mother is a Cloud Cuckoo Lander of a Spirit World Warrior who likes to cosplay as animals and sometimes wears slightly provocative Cat Girl outfits. On parents day in elementary school she dressed up as a panda and pretended to be one of the students.
Bloody Murder: Mirai's power. She uses her blood as a weapon. Deconstructed a bit: expelling more than a couple of pints of blood can make her pass out.
Body Horror: Miroku's face being distorted by tentacles.
Bookends: The anime starts and ends with Mirai and Akihito, meeting on the school rooftop at sunset.
Breather Episode: Episode 6. Mirai attempts to defeat a large, fruit-like youmu for its large bounty, only to find that the task is much more odorous than it initially seemed. When the youmu is threatened, it unleashes a torrent of stinky liquid, making it difficult to kill. Akihito, Mitsuki, Ai and Hiroomi eventually get dragged into helping Mirai fight the youmu, only for them to fail again and again and again. Eventually, they stage a song and dance number to distract the youmu...but fail to assign a person to kill it while everyone's dancing.
Canon Foreigner: Ayaka's little sister Ai was created for the TV series, and does not appear in the original novels.
Catch Phrase: Mirai's "You're unpleasant" or a variation of it.
Distracted by the Sexy: Mirai tries to distract the fruit-like youmu by dressing in a Stripperiffic costume and striking sexy poses, while Mitsuki sneaks around and attacks the youmu. It Makes Sense in Context, as this type of youmu is especifically noted to be, strangely enough, particularly attracted to human women.
Easily Forgiven: After spending a few episodes powering up, Sakura tries to kill Mirai and fails. The next episode, they are brushing each others' hair and Sakura was Shipping Akihito and Mirai. But then again, Mirai did feel that Sakura's attacks on her were justified, and they were old childhood friends.
Eldritch Abomination: Beyond The Boundary, possibly the most powerful youmu there is. It is said to appear every so many thousand years, born from the negative feelings of countless humans along a very long time period. This youmu, while weakened by the Calm, was still strong enough to create an isolated dimension where it engaged Mirai in a deathmatch, while also absorbing power from hunters and other youmu alike from all over for itself. Notably, it wasn't destroyed by the anime's end; it was only stopped by being reabsorbed by Akihito.
Eldritch Horror: There are some youmu so insanely powerful that they don't even need a physical form to exist. The Hollow Shadow is one of these. None can compare to Beyond The Boundary.
Elemental Powers: Never explicitly stated, but the Spirit Hunters and youmu alike are seen manipulating, air, water, earth, fire and ice.
Embarrassing Nickname: Hiroomi likes to call Akihito "Akkey". Akihito doesn't like it since, according to him, it sounds like the nickname of a washed up idol.
Fantastic Racism: Invoked by Akihito after Mirai admits she likes using him for "practice", since as an immortal, his wounds will always heal. He compares being singled out because of his yōmu heritage to discrimination. Mirai is also a victim of this, as her clan was feared due to their ability to manipulate blood.
Hidden Depths: Akihito is a rather sarcastic slacker with a fetish for glasses and girls who wear them.He is also deeply troubled of the fact that should anything push him into a certain treshold of physical damage, he'll turn into a raging nigh-unkillable demon that will raze everything to the ground without regard for friends or family.
Human Aliens: Most youmu are bizarre-looking monsters, but some are identical to humans.
"I Know You're in There Somewhere" Fight: Averted; it's what you'd normally expect in episode 9 based on their relationship, but Mirai does not hold back against Akihito at all, and was really attacking to kill.
Japanese Sibling Terminology: Mitsuki is fully aware that the phrase 'Onii-chan' stokes Hiroomi's siscon fetish, so she avoids it, using the word 'Aniki' whenever possible. Except, however, when there's something she wants from him...
The teacher Ninomiya uses Onii-san when talking to a handsome young waiter.
Last of His Kind: The Kuriyamas were exterminated out of jealousy and fear of their ability, and Mirai is the last member of the clan.
While Akihito is not technically this, the rarity of a Half-youmu is repeatedly remarked on.
Money Spider: Defeated youmu turn into weird lumpy gemstones, which their killer trades in for human currency.
Mundane Utility: In episode 9 Mirai uses her blood manipulation powers to pick a lock. In the same episode, Izumi lights up a dark path at night by creating a series of small box shaped force fields along the path for illumination.
He loses it briefly during the Calm, then seemingly permanently after Beyond The Boundary is extracted from him. It is safe to assume he plays the trope straight once more at the anime's end, when Beyond The Boundary is back inside him.
Offscreen Teleportation: Akihito suddenly appears to help Mirai in a battle, right after he was shown standing around in his apartment miles away. He doesn't seem to know how he got there, either.
Our Spirits Are Different: Youmu range from anything like insects to humanoids that can pass off as human and will heal all wounds over time unless their eyes are destroyed, which causes the gemstones to appear. One human youmu compares the differences between youmu to that of mammals like humans and cows. How aggressive they are also depends on the youmu, though more powerful youmu like Hollow Shadow can influence others and make even docile youmu very aggressive. Also, the most powerful youmu are apparently all formless and/or lack physical bodies until sufficient amounts of time have passed.
Akihito's so-called youmu side is actually none other than Beyond the Boundary itself.
Mirai and Izumi were in cahoots from the very beginning, and the plan was to kill Akihito as soon as possible in order to destroy Beyond the Boundary. Mirai falling in love with Akihito threw a wrench into that plan.
Sequel Hook: We have no idea why the Kyoukai no Kanata was put inside of Akihito, Hiroomi was made the head of the Nase family, as Izumi disappeared. We learned that Izumi and Miroku have Youmu inside of them, and knew each other before the start of the series. And the Kyoukai no Kanata is still inside of Akihito at the end of the anime. Although this is probably as the series is still continuing as the light novels.
Superpowered Evil Side: Akihito's youmu side. Whenever his body suffers a particularly extreme amount of damage, his youmu nature takes over, goes berserk and proceeds to destroy everything around it. As a form of reference for how strong it is, Shizuku, Ayaka and Hiroomi together succeeded in containing it for all of 5 minutes before it broke free and everything went up in flames.
This "youmu side" is actually a full-blown youmu that has been living inside of Akihito taking over, and is known as the exceedingly powerful Beyond The Boundary. Due to various reasons, it manages to fully take over during the Calm, prompting Izumi to say that if Beyond The Boundary remains in control of the body after the Calm ends, it will truly become an unstoppable menace.
Shaggy Dog Story: Episode 6 had a training montage leading up to an epic musical routine, that ended up having the group completely fail in the most crucial part.
Technicolor Eyes: Except for Akihito, every youmu or part youmu has blue/green eyes.
Mirai: I killed someone. I... I killed her with my own two hands.
In Episode 12:
Miroku (to Izumi): When you get down to it, we're in the same boat. We both harbor youmu inside our bodies.
Wham Episode: Episode 4, but especially the latter half. "HSQ" doesn't even begin to describe it. Suffice to say that describing just that half, with the emergence of Akihito's Superpowered Evil Side, would probably mean the use of a Wall of Text.
Episode 9 reveals that Mirai's mission from the start was to kill Akhito as part of Izumi's plot.
Episode 10 continues with this in a heartwrenching way. Everything seems fine and dandy, until it's revealed Akihito has been dreaming the whole time. Mirai never intended to kill Akihito, she only brought out his Youmu half from within him and let herself be consumed. She's now in an alternate Pocket Dimension of the town trying to kill it, while the now human Akihito has been comatose in the hospital.
The Worf Effect: The Hollow Shadow mostly ends up as a way to show how potently strong Mirai's abilities are, and how terrifyingly powerful Akihito's youmu side is.
The Calm has the effect of making all youmu significantly weaker.
Title Drop: In episode 7, Izumi mentions "Beyond the Boundary" in hushed tones as something that will accompany the approaching Calm, a period of timelessness.
"Beyond the Boundary" is actually the name of an extraordinarily powerful youmu. It is so strong that it could have destroyed the world at any time had it been running free. The only reason it didn't is because it had remained mostly docile inside of Akihito.
Wound That Will Not Heal: Mirai has a pinprick on her right palm where she draws her blood from. It never seems to heal, and she wears gauze at all times when she's not fighting.