Hisaya Miki

is a first-year at St. Ishiyama High School, and a member of the Six Horsemen- or the Rokkisei.

He was once a friend of Oga and Furuichi, who went to their middle school. He was friends with Oga, as he looked up to his strength and wished to be strong as well. After sometime he had to move to Nara, leaving with a burning hatred for Oga.

Appearance
Miki is a short male teenager with black hair (sometimes seen as violet) and dark eyes, often seen wearing his school's uniform. He has two scars on his left chin, as a result from an incident where he attempted to fight with a gang leader and only got injured instead. Miki also has a beauty mark under each eye.

Personality
In the past, he was shown to be a gentle child. He admired Oga for his strength and for protecting him, causing him to be grateful and view each other as friends. He desired the ability to stand up for himself and demonstrated a high level of pride, wanting to face the bully himself and not wanting to bring others into his trouble though failed due to his lack of strength.

However, his kind personality was somewhat warped when he believed Oga had "betrayed him" in the past. As a result, he developed a burning hatred for him and wished to surpass him. He states he is "allergic" to delinquents, rudely slapping Furuichi's hand away upon their meeting several years later despite having once been his friend. He demonstrated strong determination in his goal but shows disapproval of cheating and wants to prove his strength without a doubt. However, once he learned the truth of why Oga "betrayed him" (which was to protect him from a bully's wrath) he admits he simply wanted to be strong enough to protect those he cared for. He realizes his wrong and tries to befriend Oga again, though the two don't interact as much throughout the story.

History
One day after the three were coming home from an abandoned factory, Miki went back to the factory to get back a charm he forgot. When he got there, a gang that had made the factory their hang out beat him up.

Oga thinking something was wrong went back and looked for Miki, finding him beaten up by a gang, when Oga was fighting, Miki attempted to fight the gang leader, who easily beat him and, using two of his nails, which were rather long and sharp, scratched Miki in the face creating his trademark scar. But even then, Miki was grateful for Oga defending him, making him feel that he was truly Oga's friend.

On the day before he moved, the gang came to their school looking for Oga. Miki quickly went to help Oga, only for Oga to beat him up and call him pathetic. This caused Miki to hate Oga, and he later moved back, and when he entered St. Ishiyama he begged Kaname Izuma to teach him martial arts, looking to defeat Oga.

Saint Ishiyama Academy Arc
When Oga entered St. Ishiyama High School, Miki was overjoyed to finally fight Oga. He quickly started a quarrel that ended in a tie. Later after a volleyball match between Ishiyama High and the Rokkisei, the Gang's leader that had beat up Miki went looking for Oga for revenge. Miki was eager to fight him as well, but the gang leader later remembers him from the fight, in which the gang leader revealed that he was going to move to Nara as well. Miki then realized that Oga had beat him up, so the gang leader would not have a motive, and leave him alone. As such Miki felt great remorse, that he had hated Oga. Afterward, he would attempt to befriend Oga once more. Throughout the series, He never seems to talk to Oga and Furuichi much.

Mobichi Arc
While strolling around the campus, Miki sees Furuichi nearby getting into a fight with five members of the karate club. He then witnesses as Furuichi defeat all of them with relative ease. Miki approaches Furuichi and explains that the people whom he defeated were merely troublemakers, but he then brushes it off and asks how Furuichi came to such power; Miki is unimpressed with Furuichi's answer. He is then challenged to a fight, which he gladly partakes in, dealing the first attack once it commences. However, he finds that his wrists have been stopped before hitting Furuichi and is headbutted, rendering Miki momentarily immobilized.

Later, Miki secretly watches a fight between Oga and Furuichi at the river. Once they are done fighting, several of their peers arrive hoping to have a rematch with him, causing Miki to come out from the shadows and inquire whether he should be the first to have his revenge. He then stands beside the other Ishiyama delinquents as they confront the Shadow Force, who are all defeated easily afterward. Miki remains with the delinquents for a while longer later.

Powers & Abilities
Having been thoroughly trained in martial arts, he relies on his agility to evade Oga's attacks and is the only person so far who has come out of a fight with him unscathed. However, most of his own attacks, although strong enough to take down Kanzaki, fail to have much of an effect on stronger thugs like Oga and Toujou. The Izuma style finisher (the Black Owl Killer) is strong enough to take down Oga in one hit, but it must be stressed that Oga actually intended to take the blow to measure Miki's strength, and made no effort to dodge it. His own resilience does not seem particularly high, as he was quite affected by two hits from Teimou's shadow forces, and was saved from further injury by Oga. He is also inexperienced when it comes to fighting multiple opponents at once, as shown when he had trouble fighting members from Teimou's Shadow Forces. He was also one of few people who can feel Saotome using demon power, showing he has notable strength for a human being.

Techniques

 * Black Owl Killer: A finishing technique of the Izuma Eight Gods Style of martial arts. It's strong enough to bring someone of Oga's caliber down. However, due to the high power of the attack and Miki's inexperience, it causes his hands to bleed excessively from its use.

Trivia

 * Occasionally in the manga, Miki's eyes are shown portrayed as light blue.
 * His appearance resembles Kenichi Shirahama, as they are students of same ages and share taichi badge. Moreover, they were being bullied and learned Ba Chi Quan later.