A force that consists of six captains from school clubs and sports teams who have extraordinary fighting experience. They ensure that the rules of Saint Ishiyama Academy are upheld by the students, especially Oga and the other Ishiyama High students.
The Six Holy Knights are a group of six students from St. Ishiyama Academy that uphold the rules and keep those who wish to disobey those rules in line. Each member of the group is the captain or leader of their respective school clubs (excluding Miki), and each swears to protect the students and staff at St. Ishiyama from any danger from those who threaten to or actually break the rules. Whenever trouble arises, the Six Holy Knights are sure to show up and put things right by their own brutal methods.
1. Izuma Kaname: The current leader of the Six Holy Knights, Izuma Kaname is the most powerful and dangerous member of the six current members. He is the leader of the current Student Council at St. Ishiyama, and mostly deals with issues that arise in the scheduled meetings. He comes across to others as a average person, but to those who truly know him, his very presence instills bone-chilling fear into those who have gotten on his bad side. He acts as a mentor of sorts to fellow member Miki and trains him as a teacher would teach their pupil.
2. Nanami Shizuka: The only female member of the Six Holy Knights, Nanami Shizuka is the current captain of the Archery Team at St. Ishiyama Academy. At first glance, nothing special stands out about Nanami other than the fact that she is a beautiful girl, but under that beauty is a cold, dangerous person that deals swift justice to those who break the rules. She also keeps the other male members from stepping out of line.
3. Miki Hisaya: The only member of the Six Holy Knights that isn't shown to be a captain or leader of a specific school club, Miki Hisaya is constantly training so that he can continue to become a more powerful being. Unknown to most, Miki has old ties to both Oga Tatsumi and Furuichi dating back to their days in middle school. Unfortunately, several events that took place back in their past caused a major rift between the former friends and thus Miki vowed to become stronger than Oga could ever humanly be in order to one day defeat him in a fight.
4. Gou Hiromichi: The current leader of the St. Ishiyama Radio Club, Gou Hiromichi is the most ruthless member of the Six Holy Knights in the sense that he is always looking looking for a fight. Of all the members, he is the most muscular and tends to use his brute strength to uphold the rules and enforce punishment on those who break the rules.
5. Ichiro Shinjo: The current leader of the St. Ishiyama's Union Boxing Club, Ichiro Shinjo is a master of close-quarters fighting and has the impressive feat of ending every match that he has ever entered in a single, punishing blow. He is somewhat reckless due to his undefeated streak and isn't afraid to settle issues with his fists.
6. Sakaki Mitsuteru: The current leader of the St. Ishiyama Kendo Team, Sakaki Mitsuteru is a master of swordplay and wields his wooden sword with deadly efficiency. He is the least talkative member of the Six Holy Knights and is rarely seen with his eyes open. He has a liking for "moe-like" things, as evident in the pin he has on his collar.
Aside from their normal school lives, the Six Holy Knights are tasked with upholding the order and rules of St. Ishiyama Academy while protecting the student population from those who wish to do harm.
The Six Holy Knights are particularly skilled in various methods of fighting, especially when it comes to powerful attacks that they use upon their opponents. While some utilize brute strength or speed, the others employ special techniques upon their opponents. Below is a list that features each of their specialities:
1. Izuma: The strongest member of the Six Holy Knights, Izuma utilizes his impressive strength combined with specialized techniques in combat. He harbors a special set of rare skills that gains him the edge in combat and has been training Miki to become a stronger person.
2. Nanami: Not much is known in regards to the full powers and capabilities of Nanami at this time (since she has yet to get into a fight that is shown or spoken about). It is assumed that she is quite powerful. It is also not known if she utilizes any special abilities or techniques like Izuma or Miki.
3. Miki: Miki utilizes special techniques combined with his strength that he has been training hard at over the past few years, especially in his training with Izuma. His strikes are very powerful and can usually K.O. his opponent in a single blow.
4. Gou: He relies on his brute strength to gain the advantage in battle. It is not known if he utilizes special abilities or techniques like Miki or Izuma, but he is a force to be reckoned with.
5. Ichiro: He relies on his expertise in close-quarters combat, agility, and strength to gain the advantage in combat. Being the high-level boxer that he is, he has a special punch that has K.O'ed every opponent that he has faced with a single, crushing blow. It is not known if he utilizes any special abilities or techniques like Izuma or Miki.
6. Sakaki: He utilizes his impressive agility combined with his dangerous sword skills in order to gain the advantage in combat. Sakaki uses a wooden sword that he trains with as the leader of the Kendo Team. It is not known if he has any special abilities or techniques like Izuma or Miki.
The Six Holy Knights are first introduced in both the Beelzebub anime and manga after the conclusion of the Ishiyama High Arc, following the summer after Oga smashed the school building. With the entire Ishiyama High building compromised, the students are sent out to other schools in the surrounding area as a temporary measure. Oga, Furuichi, Shimokawa, the MK5, Aoi Kunieda, several members of the Red Tails loyal to her through Nene Omori, and the other members of the TKKH along with some of their followers find themselves being sent to the pristine St. Ishiyama Academy to resume their courses. It doesn't take long for certain members of the Ishiyama High brigade (mainly Shimokawa, the MK5, and lesser thugs) to start preying on the mild-mannered students that make up the majority of the academy's roster. When the lesser thugs and MK5 begin harassing the students, they attract the attention of the Six Holy Knights, who are aware of the band of delinquents that transferred from Ishiyama High to St. Ishiyama and now are causing issues. After word spreads of the harassment of students by members of the Ishiyama High brigade, Miki and Ichiro team up against the MK5 and quickly crush them in a brief fight on the roof of the academy. Shimokawa is also dealt with by members of the Six Holy Knights after he continuously harasses the female students to the point that he became a target for them to deal with. After their defeat at the hands of the Six Holy Knights, the MK5, Shimokawa, and the other troublemakers are not heard from again (possibly due to expulsion for their actions or from their injuries).
Furuichi is the first of the remaining Ishiyama High students to encounter one of the members of the Six Holy Knights without being a marked target for them to deal with when he meets Miki while buying a drink at the vending machine. Furuichi remembers Miki from their days in middle school and tries to engage him in conversation, but Miki has not much interest in doing so and warns Furuichi that Oga and the Ishiyama High students should not fight with the Six Holy Knights. Later that day, Oga and Aoi come across both Ichiro and Sakaki Mitsuteru in the hallway outside of Azusa Fujisaki's homeroom. They get involved in a minor confrontation that neither side wins in the end and thus the two of them encounter the Six Holy Knights for the first time. For the time being, the remaining students from Ishiyama High are getting by without any major problems to warrant any trouble from the Six Holy Knights, but that all changes when two reckless students pull off a dumb attack involving Shiroyama, one of the loyal followers of the TKKH's Hajime Kanzaki.
While talking to two members of the Red Tails (aligned with Aoi Kunieda through Nene Omori), Shiroyama notices two male students from St. Ishiyama harassing the girls and steps in to deal with them. He gets the agitators to stop bothering them, and tells the girls to go, unaware of what the students he stopped are planning to get back at him. For their trouble, he lets them each have a free punch at him, which they agree to since it will allow for their plan to be set in motion. While one student takes a swing at Shiroyama, the other disappears to go "fetch" something. He then reappears in a doorway above Shiroyama and say something that catches his attention, causing him to look up at the two boys on the stairs. As he starts to move his head so that he can look up at them, they heave a massive piece of gym equipment over the railing and directly at his body. It is not shown what happens next, but the resulting impact leaves Shiroyama with terrible injuries that require medical attention. Horrified, the two girls from the Red Tails report back to Nene what happened, and when the news of the cowardly attack reaches Kanzaki, he goes into a wild rage. Looking to settle the score with the two students who dared to pull such a cowardly attack upon his loyal follower, Kanazki wanders the halls of St. Ishiyama armed with a baseball bat, on a mission to enact terrible revenge upon them. The two idiots in question are in their homeroom enjoying themselves for pulling off the shocking attack upon the surprised Shiroyama, and it isn't long before Kanzaki narrows down where they are and breaks through one of the windows, sending the students inside into a panic. Kanzaki tells the terrified students that he is going to kill them all, and with a mighty toss, throws his baseball bat at the blackboard with such force that it breaks it upon impact.
When the two troublemakers who injured Shiroyama bring up how these choice of action will result in his expulsion from St. Ishiyama, the furious Kanzaki grabs one boy by his collar and lifts him into the air, telling him that he does not care. At this time, Miki steps in to protect the frightened students from danger and with one powerful attack, sends the shocked Kanzaki flying across the room and results in him being knocked out when he slams into the wall at the back of the classroom. Moments later, Oga, Aoi, Nene, and the other Ishiyama High students who followed her in their attempts to stop the vengeful Kanzaki from attacking the two students arrive on the scene to find him slumped over unconscious against the wall. It is at this time that Oga and Miki come face to face with each other for the first time since their days in middle school, but Oga does not appear to remember who he is. Later that day, Oga comes across four of the Six Holy Knights soliciting on the roof of the academy after he and Furuichi noticed a "trap" and he decides to take a look at the Six Holy Knights for himself, even if it is only 4 of them. Standing on the roof is Miki, Ichiro, Gou Hiromichi, and Sasaki, who have been waiting for Oga to arrive so that they can take a good look at the one who stood up to Ichiro earlier. One of them pokes fun at the fact that he intends to fight all of them alone, but they are cut short when Natsume arrives and tells them that it "all works out" since both Aoi and fellow TKKH member Tatsuya Himekawa have accompanied him to the roof and now makes it a fair four-on-four fight. Reckless in his logic, Ichiro charges at Oga, daring him to throw a punch at him, which Oga gladly obliges to. Rushing forward, Oga connects with a brutal right-handed punch that sends the dazed Ichiro soaring through the air and crashing into the fence that prevents anyone from falling off of the academy's roof. With that, the first official battle between the Six Holy Knights and the Ishiyama High students begins. Oga and Miki face off against each other for the first time while around them the other members of each group face off against each other. In the process of the fighting, the recovered Kanzaki arrives at the scene and tries to get back at Miki for what he did to him earlier that day, but is sent flying high into the sky by Oga for getting in the way of his fight.
After a unknown amount of time passes, the fight on the rooftop is interrupted by the arrival of the 5th member of the Six Holy Knights: Nanami Shizuka. She scolds her four fellow members about their choice in actions and tells them that "he" isn't pleased with their decision to take on members from Ishiyama High. A wave of fear sweeps through the four members in question, for they know that their actions have caused their leader to become displeased with them regarding the situation. Standing at the doorway to the stairs, Furuichi, Azusa, and Kazuya Yamamura, who have been watching the fight between the two factions, are surprised when a man wearing glasses appears behind them and walks out through the doorway onto the scene of the disturbance. This marks the arrival of the strongest member and current leader of the Six Holy Knights, Izuma Kaname. He wishes to end this fight and to deal with the situation in a more proper manner, but is interrupted when Hidetora Toujou, the most powerful member of the TKKH arrives on the rooftop after being called from his construction job about a fight taking place. When Izuma tries to defuse the tense situation with words, Toujou takes no notice of it since he is spoiling for a good fight and prepares to engage the enemy in combat. With a mighty swing, Toujou connects a powerful strike on Izuma's body, but is stunned when the hit hardly even hurts his opponent. Concerned, Miki intervenes in their fight by using the forbidden technique on the unsuspecting Toujou, but even the raw power of this impressive attack hardly bothers the grinning Toujou. The Six Holy Knights end the fight, and tell Oga and company that the police can entertain them if they choose to remain on the campus. With that, Oga and the others depart from the scene.
The following day, Oga along with all of the Ishiyama High students that were involved in the scuffle on the roof come to find out that they have been expelled from St. Ishiyama Academy for their actions with the Six Holy Knights. Furuichi reads off their names that have been posted onto the blackboard in their classroom, and is horrified to realize that he too has been expelled from St. Ishiyama, even though he didn't even get involved in the fight yesterday. They seek a meeting with the councilor regarding their expulsions, and discover that the Six Holy Knights are given special privileges in regards to what they do around campus, thus the reason that they will not be receiving any sort of punishment or discipline. Not amused by this, TKKH members Aoi and Himekawa argue with the councilor regarding their situations, and eventually the councilor strikes up a deal with them. Their expulsions are on hold for a month, and they will face off against the Six Holy Knights in one of the sporting events for the upcoming St. Ishiyama Festival. If they win, they will not be expelled from the academy, but if they lose, their postponed expulsions will become official and they will be forced to leave. Not satisfied with the fact that the Six Holy Knights have nothing to lose if the Ishiyama High students somehow manage to beat them, Himekawa sweetens the pot by suggesting that if the Six Holy Knights lose, they should be stripped of their powers. Interested in this idea, the councilor agrees to his deal and makes the upcoming meeting of the two factions at the festival official.
Oga and the rest of the Ishiyama High students are informed several days later that the sport that they will be playing in their match against the Six Holy Knights is volleyball. Aoi soon discovers that the majority of her classmates do not possess much athletic talent outside of brawling with others, so she takes it upon herself to get them to practice hard for their upcoming match. After some practice sessions that do not go well and a surprise makeover that members of the Red Tails give the flabbergasted Himekawa, Aoi eventually gets help from Hildagarde to help train the male students so that they finally become decent at volleyball. Worn out from the training, Oga, Furuichi, and Baby Beel leave the gymnasium and head off to get away from the area, but they are attracted to a small dojo that sounds of fighting emanate from. Inside, they find Miki training hard with punching bags in his continued efforts to become the strongest being that he can possibly be. They eventually crash Miki's training session and before long Oga is handed a spare set of karate clothes that Miki had laying around so that they can finally fight against each other. They engage each other in combat, with most of Oga's attacks missing the mark and with Miki connecting on the majority of his attacks. With a powerful strike, he sends the surprised Oga flying across the room and smashing into the wall of the dojo. They end their fight against each other, since Miki has better things to do and with that, the battered Oga, worried Furuichi, and peeved Beel depart the dojo and make their way home. They run into a disapproving Aoi and some of her Red Tails followers by the gym, who wishes to know why they left the volleyball practice early and as to why Oga looks roughed up. Furuichi responds by telling her that should not worry about them and that they would be there for practice tomorrow.
After getting into a fight with Toujou alongside the river later that evening, Oga looks forward to their upcoming volleyball match against Miki and the rest of the Six Holy Knights at the festival, but before that can happen, Furuichi, Aoi, and the Red Tails eventually become involved with the class-run maid cafe that Azusa Fujisaki and her classmates are hosting for the festival. Looking for something to do apart from getting ready for the upcoming volleyball match, the interested Furuichi comes across Azusa's class cafe that is open for the duration of the festival. When Kazuya Yamamura brings word that the Six Holy Knights are attracting the majority of the student customers to their cafe lounge, Furuichi decides to step up the cafe's game by enlisting the aid of a irritated Aoi to help them out. Later in the day, Nene Omori and the Red Tails come across the cafe and are stunned to see Madame Aoi dressed in a cute pink maid outfit greeting them with kind words. When told that the fight against the Six Holy Knights has already begun and that they could help, Furuichi manages to convince them to don maid outfits and help serve the "masters" who showed up to the cafe. Unfortunately, the Red Tails are too agressive and strict in their behavior towards the students who come to the cafe and after some failures, Hilda appears to order something off of the menu. Brought to tears over the continuing failure of his ideas, a crying Furuichi begs Hilda to help him with the cafe, and before long, Hilda takes up his offer and transforms the classroom into a castle-like dining room fit for royalty. At this time, thugs from Teimo Tech appear and wish to eat at their cafe, which doesn't take very long for them to cause issues for the cafe and after becoming agressive with the female staff, are swiftly crushed by Hilda and her fellow maids. Outside in the hallway, the lone Teimo Tech punk that escaped goes to call in more of his men, but is shocked to see that they have been already defeated by the Six Holy Knights and that the students from Ishiyama High block his escape from behind. It is here that the two sides come face to face prior to their volleyball match after making swift work of the thug from Teimo Tech.
Later in the day, the long awaited match between the Six Holy Knights and the students from Ishiyama High finally begins inside of the gym as hundreds of students from St. Ishiyama attend to watch the match. After the match starts, Oga and Toujou begin making costly mistakes or perform blatant fouls for their team since they do not fully understand how to play volleyball (as evidenced by Toujou dribbling the ball and Oga dunking it over the net). Irritated by these issues, Aoi has them take a time-out so that they can get their plan together, and the musing Himekawa suggests that if they are going to commit fouls, they should commit them in ways that allow for them to take advantage of against the Six Holy Knights. With their new method of gameplay agreed upon, Oga and the others begin "fouling" their way within striking distance of winning the match against their rivals, but it is at this time that Izuma steps up his game and begins serving balls traveling so fast and with such force that the hapless Aoi can't dig them and causes them to fall behind once again. The horrified Furuichi replaces the injured Aoi for several matches while the Red Tails and Hilda attend to and look over her wounds on her arms from trying to return Izuma's powerful serves. After several matches go by, the determined Aoi makes her return to the floor, vowing to dig every one of Izuma's dangerous serves so that her team could do their best to defeat the Six Holy Knights and not be expelled. With a final few rallies, Oga seals up the win for the Ishiyama High students as he crushes a powerful spike that lands inbounds past the stunned members of the other team. With the match over, Oga and his fellow classmates win back the right to remain at St. Ishiyama and the Six Holy Knights give up their powers and status at the academy as agreed upon. But before they can hardly even begin to relax from the match ending, a mysterious person known only to Miki, Oga, and Furuichi arrives at the gym to enact his long-awaited revenge upon Oga Tatsumi.
That mysterious person turns out to be none other than Reiji Kiriya, the feared Viper who three years ago was publicly humiliated by Oga during a fight back in their time in middle school. Kiriya has returned from his three year absence in Nara to enact his terrible revenge upon the man who scarred his face by using his own razor-sharp nails on his own face. While the majority of the people within the gym do not recognize him, his unexpected arrival stun Oga, Miki, and Furuichi, who remember the series of events on those cold winter days three years ago that ended with both Kiriya and Miki moving away to Nara in the direct aftermath of those dark days. Confident that he will demolish the hapless Oga, who is still bound by the special rules that will cause him to be expelled if he gets into another fight or disturbance, Kiriya makes his move and introduces some of his delinquent friends from Teimo Tech, who arrive to take the student audience hostage as a bargaining chip over the Six Holy Knights and Oga's fellow Ishiyama High classmates. With the hostages facing a brutal beating if any of the Six Holy Knights or Ishiyama High students make the wrong move, Kiriya begins his assault upon his rival, launching multiple attacks upon Oga's body since he knows that fighting back against him will get his rival expelled from St. Ishiyama. Unable to fight back, Oga endures the blows and does his best to dodge them while the others look on with concern, since they know that sooner or later Oga would get irritated enough to break his resistance and strike back at Kiriya. Before long, Miki steps in and confronts Kiriya after he is tossed a aluminum baseball bat to use against Oga in this one-sided fight, bringing up his involvement in the events of three years ago.
After Kiriya remembers just who Miki is, Miki is blindsided by a punishing two-way attack that sends him flying across the gym floor and crashing down on the ground. Standing behind where he landed are four bald men, known to most as the fearsome Shadow Group that hails from Teimo Tech and has joined up with Kiriya in his quest for revenge upon Oga. Knowing that this will be a tough situation, Oga and Miki decide to team up in order to deal with this dangerous situation, with Oga taking Kotaro, Unsho, and Kiriya while Miki deals with both Takumi and Kosei. Charging forward at full speed, Unsho slams his broad shoulder into Oga with such force that it sends him sliding backwards across the gym floor, doing his best to defend himself against the pushing attack until he manages to bring the stunned Unsho to a stop. Puzzled, Kotaro wonders how Oga managed to stop Unsho's usually unstoppable advance, and before he knows it, Oga launches a "super" version of his fabled Burying Punch, slamming his fist into the gut of the flabbergasted Unsho with such force that it sends him flying across the gym, colliding with the stunned Kotaro and sends both of them smashing into the wooden bleachers with such force that they get stuck in them. Meanwhile, Miki faces off with Kosei and his dangerous num-chucks, and with a single strike, manages to not only shatter Kosei's weapon into pieces, he brings the shell-shocked Kosei down with a single hit. Watching in pure disbelief, the stunned Kiriya watches as the feared Shadow Group from Teimo Tech gets utterly humiliated in battle against both Oga and Miki, and before he knows it, he becomes the target of Oga's wrath.
While Oga and Miki are busy singlehandedly humiliating the feared Shadow Group in battle, Izuma and the other members of the Six Holy Knights along with the members of the Red Tails go around the gym and swiftly deal with all of the Teimo Tech punks that are holding the students hostage. After the Shadow Group is defeated, Kiriya tries to play the hostage card against Oga and the others, but he is stunned to see that all of the men from Teimo Tech have been crushed while he was distracted with the battle and that he now has no leverage to use. Annoyed with Kiriya and reved up from his short-lived fight against the two members of the Shadow Group that he took out, Oga turns his attention to the horrified Kiriya and grabs him by the shoulder, causing the frightened Kiriya to turn his head around to see just what Oga intends to do to him. Unleashing his demonic powers that his bond with Beel grants him, Oga is surrounded by red flames as he prepares to take out the trash that is Reiji Kiriya with one hit. Flabbergasted and scared witless by what he is seeing, Kiriya begins to freak out, and before he can escape, Oga delivers a punishing Zebul Blast uppercut that sends the stunned Kiriya flying high into the air, his clothes being ripped away by both the intense power and strength from Oga's strike. The powerful attack also lifts several of the horrified members of the Shadow Group and most of the captured punks from Teimo Tech high into the air and also rips all of their clothing away apart from their undergarments. After several seconds, the battered Kiriya along with the other Teimo Tech thugs crash back down on the gym floor, in shock and disbelief from the impact of Oga's powerful Zebul Blast. When the ordeal is over after the panicing Kirya and the Teimo Tech punks flee from the gym, Izuma rectifies the tense situation by telling the stunned crowds that Oga's demonic powers was all just a "act", which gets the audience to cheer thinking they watched a awesome illusion. Izuma tells Oga as he walks past that he should control his demon powers better, and before Oga can respond to his comment, Izuma leaves the gym.
In the days after the St. Ishiyama Festival, the members of the Six Holy Knights return to the regular lifestyle of the student population, having lost their rank and powers when they were defeated by Ishiyama High in the volleyball match. Izuma resumes his duties as the leader of the student council while Shizuka returns to being the leader of the archery club in-between her classes. So far, the other members of the Six Holy Knights have yet to be shown. When the tough, powerful new teacher by the name of Zenjuro Saotome arrives at St. Ishiyama Academy in order to take over teaching duties for the special class of Ishiyama High students, this shifts the balance of power at the academy. Izuma, Toujou, and Oga quickly find this out when Zenjuro interrupts their long-awaited grudge match against each other and swiftly demolishes all three of them with a punishing set of punches.