Itogami Island. Akatsuki Kojou, an ordinary high schooler, bids farewell to his normal life in the Demon District of Itogami after an incident leaves him with the abilities of a vampire, more specifically, he is the Fourth Progenitor, an immensely powerful vampire once thought to be the product of mere legend. As a result, Kojou attracts the attention of the Lion King Organisation, which sends an apprentice sword-shaman, Himeragi Yukina, to monitor and dispose of Kojou should he pose a threat. However, Himeragi’s primary objective takes a backseat as she and Kojou are forced to form an impromptu alliance in order to subdue other forces which disturb the peace.

As a middle schooler, Himeragi is slightly younger than Kojou, who is in high school. As a result, the ever-serious Himeragi addresses Kojou using the well-known word “senpai”. Due to this, their relationship is quite clear in the beginning: that of the senpai and his kouhai. Due to their current standings in education, Himeragi’s kouhai role is not one which is implied as with many other characters, she makes it fairly easy to understand. From another perspective, one could take into account that she is still only an apprentice sword-shaman from the Lion King Organisation and therefore, not only is she Akatsuki Kojou’s junior from purely an educational point of view, but she serves as a kouhai within her line of work too.

18-year-old Nakajima Atsushi’s life is turned upside down when he is abruptly kicked out of the orphanage in which he stayed, plagued by hunger, homelessness, fatigue, and eerie stories of a mystical tiger roaming the streets. While starving on a riverbank one day, Atsushi saves the eccentric Dazai Osamu from drowning. It turns out that Dazai works for a firm of supernatural investigators which tasked him with investigating the same tiger which has plagued Atsushi. As circumstances change, Atsushi is left with no choice but to join the Detective Agency, helping them resolve cases that are beyond the jurisdiction of normal authorities.

As it turns out, the tiger that had been terrorizing the orphanage and left Atsushi homeless, is the same tiger that had been spotted around the streets of Yokohama; the same tiger Atsushi greatly feared, was Atsushi himself. Around the world exist people who harbour supernatural abilities, known as Ability-Wielders. Atsushi is one such Ability-Wielder and knowing this, Dazai saw it fit to bring him into the Detective Agency, where several other Ability-Wielders exist and help protect Yokohama City from threats supernatural in nature. Atsushi not only learns the basics of abilities from Dazai, but also reveres him as someone who is competent, crazy and also inspiring in his ability to pull just about anything out of the bag when push comes to shove.

Ever since he watched a volleyball ace dubbed “the Little Giant”, Hinata Shouyo has been crazy about all things volleyball and wished to follow in his footsteps. Forming an impromptu team in middle school and entering a tournament, Hinata tastes true disappointment when his team is decimated in the first match of his first-ever tournament by the “King of the Court”, Kageyama Tobio. Riled up by the crushing defeat, Hinata joins Karasuno High School’s volleyball team, vowing to one day surpass Kageyama – but how can he do that when Kageyama becomes his teammate? Given his short height, Hinata initially struggles to find a place in Karasuno’s starting line-up, but Kageyama has own issues that only Hinata can help fix. As a result, the two are forced to put aside their differences and work together in order to help Karasuno High School have one of the strongest volleyball teams in Japan.

Excitable, enthusiastic, energetic and emotional, Hinata Shouyo is physical evidence that the saying was in fact true – dynamite DOES come in small packages. Coming into Karasuno as a first year with very little real volleyball experience as a result of his middle school not being all that serious about the sport, Hinata finds it difficult to cope with learning basic volleyball technique and skill. However, an unorthodox combination play with Kageyama sees the both of them becoming the ace-in-the-hole for Karasuno. Given the number of older students in the Karasuno line-up, Hinata and Kageyama are both kouhais in classroom and on the court. Given his driven and enthusiastic approach, as well as his diminutive stature, Hinata fits the bill not only as a kouhai character, but as an ototo as well!

One hot summer day, Ariyoshi Juna and her boyfriend, Tokio, decide to head out on a joyride to see the sea. However, a strange and abrupt accident leaves Juna dead and to make things even stranger, Juna leaves her body and sees horrifying visions of the end of the world, the slow but steady stagnation of the Earth. In death, she meets a wheelchair bound boy named Chris, who tells her of the impending doom of our planet and gives Juna a lifeline: she can come back to life, granted that she accepts the responsibility of being the supernatural force that has the potential to save the Earth from destruction: the Avatar of Time. Eager to return to her life, Juna accepts, but the decay of the Earth and human society run deeper than she could ever have imagined.

Juna was your average Japanese teenage girl – a consumer and subscriber of the way in which society runs. To her, the environment was no real concern, she knew nothing of the truth behind the food she eats, the pollution that sullies the land and the extent of the pain felt by the Earth itself. Coming back to life as the Avatar of Time was difficult for her as she longed to return to the way she once was, but the effect of knowledge on an ignorant mind left her incapable of truly re-assimilating into modern culture. Guided by Chris, Juna struggled, argued, toiled and eventually understood what it meant to be the Avatar of Time, how to carry out her duties to calm the injured Earth and to understand humanity itself.

Now that his parents work somewhere else, high school freshman Usa Kazunari has to start living alone and moves into a boarding house, expecting a quiet life of independence. However, he is forced to abandon those pretty ideals when he moves into the Kawai Complex, living in the same space as some of the most eccentric characters he has ever met. In addition to his perverted roommate, Shirosaki, the alcoholic Nishikino Mayumi, and Watanabe Sayaka, a college student who enjoys leading men on, Usa meets the shy and quiet Kawai Ritsu, a senior student at his school, and finds himself absolutely smitten.

Usa Kazunari, the average high school boy who develops a crush on a cute girl slightly older than him. New to his living environment and to the theme of love and romance, Usa struggles quite a bit in the beginning. However, his senpai-kouhai relationship with Kawai Ritsu gradually improves and grows into something more than that; a relationship that beckons romance but also shies away from it. From a romance standpoint, one could say that both Usa and Ritsu assume the kouhai role while everyone else in the Kawai Complex is the senpai, but for now, Ritsu’s lovestruck junior is who we’ll pay attention to (sorry, Sayaka).

As a result of taking in a bunch of abandoned kittens, second year high schooler Kanda Sorata has to move into Suimei High School’s infamous Sakura Hall dormitory, a place where eccentric misfits reside. There he meets Misaki, an energetic animator, the playboy Jin, the recluse Ryuunosuke, as well as Chihiro, the party girl, art teacher and their dorm manager. Sorata’s childhood friend, Nanami, pushes him to find new owners for the cats so that he can quickly move out of Sakura Hall, but his desire to move out is whittled down when he meets second year Shiina Mashiro, a world-class artistic savant who has hopes of one day becoming a mangaka. Mashiro clings to Sorata like glue and, encouraged by each other’s commitment to their dreams, the two grow out of their initial roles and become catalysts of change in the people around them.

A young man with ambitions of one day becoming a game developer surrounded by a plethora of eccentric but otherwise artistic students, Kanda Sorata is our next kouhai for the simple fact that third year student Misaki literally calls him “Kouhai-kun”. While it now serves the use of a term of endearment, Misaki’s relationship with Sorata, being that of senior and junior student, makes the strange nickname most appropriate.

Being the sole survivor of a clan of warriors who use their blood as a weapon, Kuriyama Mirai’s job is to hunt down and kill “youmu”, dangerous creatures known to be the manifestation of negative human emotions. When she runs into Kanbara Akihito, a rare half-breed of youmu and human, Mirai panics and plunges her sword into him, realising only later that it is a futile exercise – Akihito is an immortal being. From that moment on, the two of them form a strange friendship based on Mirai’s constant attempts on Akihito’s life, with Akihito later inviting her to join the Literary Club, where Nase Hiroomi and Mitsuki, powerful Spirit World warriors, spend their time. The friendship amongst them strengthens and is eventually put to the test as the seemingly inevitable emergence of the most powerful youmu, Beyond the Boundary, nears.

Mirai, being the sole survivor of her clan, has had to learn the tools of her trade the hard way, with no real modus of support to help her. As a result, in addition to being a complete ditz, Mirai isn’t too good at youmu hunting and her confidence is at an all-time low. However, with Kanbara Akihito being both half-youmu and her upperclassman at school, Mirai learns more about herself, the youmu and of course, a little about romance too!

Happy-go-lucky high school student Hirasawa Yui sees the fire in her heart ignited when she spots a poster promoting her school’s Light Music Club. She joins, but she realises fairly quickly that she is unable to play an instrument. Upon attending her first club meeting, she quickly tries to tell the other members about her problem, but they convince Yui to stay in order to avoid the club’s disbandment and she then becomes the new guitarist. With the help of the other members, Yui learns to play the guitar somewhat, but with the school festival not so long from now, will Yui and the Light Music Club be ready to dazzle audiences?

After the first season of K-ON!!, Yui, Mio, Ritsu and Tsumugi become second years at school and every new year means fresh blood. Enter Nakano Azusa, a serious, committed but sweet young girl who becomes the Light Music Club’s only new recruit as a rhythm guitarist and dreams of one day playing in a jazz band. Being the youngest in the club, Azusa has someone she greatly admires: Mio; for her maturity and her musical capability. Azusa’s role as the kouhai to the original members of the Light Music Club extends only to their classes in high school, when it comes to music and versatility with musical instruments, Azusa trumps all of them and later even teaches Tsumugi how to play guitar. K-ON!!

Takanashi Souta has a serious obsession with anything small and cute, so when the small and cute Taneshima Popura approaches him to recruit him to work at a family restaurant called Wagnaria, he cannot refuse. Takanashi enjoys doting on Popura, who has developed a complex over how young she looks. Under her guidance, Takanashi learns the various tasks he must accomplish as a Wagnaria employee, as well as the true terrors that await him in the form of his eccentric colleagues – katana-slinging floor chief Todoroki Yachiyo, the intimidating head chef Satou Jun, the enigmatic and well-informed sadistic sous chef Souma Hiroomi, the lazy manager Shirafuji Kyouko, as well as androphobic waitress Inami Mahiru. Working!! follows the day-to-day antics of the wacky employees of Wagnaria and Takanashi’s assimilation into the fold – producing hilarious shenanigans and brilliant service that one can only get at Wagnaria Family Restaurant.

Despite what it may look like, Takanashi is actually younger than his senior at work, Taneshima Popura. As such, Takanashi is her junior on two fronts; in age and in work experience. Despite these roles being assigned to them, Takanashi and Popura’s relationship does not seem like the conventional senpai / kouhai relationship due to the fact that Takanashi dotes on Popura the same way an older brother would his little sister. However, on many occasions throughout the series we see Popura quickly assume her role and responsibility as senior, giving her kouhai, Takanashi, much-needed advice and guidance.

22-year-old Onizuka Eikichi is a reformed former biker gang leader who has the noble and lofty ambition of becoming a high school teacher… because he’d like to meet sexy high school girls… Anyway, despite relentless attempts by strict administrators and a class of some of the most horrible children, Onizuka pushes toward his goal. His unorthodox teaching methods see him bring an entirely different voice to a school and class tired of the same old authoritarian droning. 22-year-old Onizuka Eikichi – school teacher!

So we’re sure there is much confusion as to why an educator would be considered a kouhai – they stand above just about everyone else in their respective classrooms, so why? Well, in Onizuka’s case, being the youngest and the newest teacher puts him in this position relative to his colleagues and to some extent, his superiors. His initial struggles to make much of an impression leading into his first few days on the job and his completely unique teaching method puts him directly into the role of the belligerent, messy junior colleague who hasn’t quite yet developed the necessary skills needed to do the job the same way it has always been done. Due to this, it makes perfect sense to place Onizuka into the kouhai mould and moreover, due to his unrelenting, unorthodox, yet highly successful way of doing things, Onizuka Eikichi can be seen as one of the most iconic and edgy kouhai characters there has ever been.