Kouha Ren (練 紅覇, Ren Kōha) is the Kou Empire's former Third Imperial Prince. He was a General of the Kou Empire's Western Subjugation Army along with his brothers, Kouen and Koumei. Kouha is the owner of the Djinn, Leraje. He is a Dungeon Capturer, capturing one Dungeon and is one of Judar's King Vessels. After the Kou Empire's civil war, he was sentenced to be exiled by Hakuryuu upon Kouen's request for mercy. He is now currently living in Samon Island, which is owned by the Kou Empire, with his brothers.
Kouha appears as a young boy with an androgynous aspect. He has long pink hair, short in the back and has three braids on his fringe, and pink eyes. He also wears a blue hat with a design on it that has golden wings, two long red veils and a white chinese-style dress with a pair of shorts. He also wears two golden bracelets, each with a green jewel, but his Metal Vessel is his sword.
After the three year timeskip Kouha seems to have gotten a lot taller, as well as having grown his hair out long enough to cause Alibaba to mistake him for a beautiful woman. 
He appears to enjoy hitting his attendants, especially the females. He also has a twisted personality - commonly known as "yangire" in Japanese - and takes pleasure butchering his enemies. He also loves the sight of blood and is well known in Kou Empire for his eccentric personality.
Kouha also has a nice and extremely caring side to him, especially towards his attendants. When they were thrown away and left to rot, Kouha came to them asking for magic users. He bandaged them, clothed them, smiled at them, and appointed them. Though they think they are ugly because they have to be bandaged up, Kouha tells them that they aren't ugly, that it is proof that they have seized their power and paved their way of life, and adds that it's charming. This is why his servants love him so much now, and even ask to be hit by him.
Aside from that, Kouha is loyal when it comes to his older brothers. He respects them and is willing to support them the best he can. It is also shown that he likes when he receives praise from his elder brothers and seems to quite comfortable with them. He has dropped some formal tendencies when with them which can be showed when he addresses his eldest brother by a nickname in place of his full name. However, he still shows that his loyalty will never waver.
Unlike his older brothers, he lived with his mother at the deepest end of the palace due to the mother suffering from a mental illness, secluding both of them from a life with a father. Another factor contributing to it was Kouha's violent attitude, which was caused by Koutoku Ren's action of turning a blind eye to the situation and offering no support and his mother's actions of acting like a baby.
After a short introduction of introducing themselves, Kouha attacked them; slicing Kouen with a sword and pummeling Koumei whilst yelling "I'm gonna pummel you both! Then you'll see how that pig Koutoku leaves you to rot too! Because useless people deserve to die!! And when people are broken we become useless!!"
Koumei approaches Kouha and states that the reason why everyone was keeping away from them was due to his attitude and then offered the advice that all he had to do was acknowledged for his worth to this country and then he and his mother would have a legitimate place to live. Kouen assures Kouha that his ability with the sword is really something else. (due to him slicing him.)
Whilst Kouen questions Kouha's ability to understand such difficult words at five to Koumei, Kouha interjects and blankly states with a smile that he isn't five, he isn't Kouha but simply his 'mother', while gesturing to his own mother that she is Kouha. He adds that he is the proud and beautiful mother with three cute braids in her bangs.
Kouen agrees with a trailed off 'Okay..', but reminds Kouha that to them, Kouen and Koumei, he is always Ren Kouha, their little brother, and that he should keep that in mind when he gets tired of 'this' (possibly in reference to his attitude to his mother). Kouha doesn't know what to say as Kouen gives an affectionate pat to his head and tears slide out of his eyes.
After the death of the Emperor and his heirs in a fire, Kouha's father became the Second Emperor, making him the third Prince.
When Kouha was a child, against the advice of older people, he chose outcasts and odd people to be part of his army; ones that were failed experiments of artificial Magicians—such as Jinjin, Junjun and Reirei, low standing swordsmen joined or born to various clans, and warriors who were exiled into the wilderness after their ancestors planned a revolt 120 years ago.
People started to talk about Kouha. They would say that it is to be expected that Kouha would gather twisted people. They said that since his childhood, he had an eccentric personality and liked the sight of blood. They also said that this must be from the fact that his mother lost her sanity for a long time, and that even if he becomes a general, its impossible for him to be suitable as Kou's Emperor.
Kouha tells his subordinates that the country isn't expecting anything from them, and that the way things are now, they can live their lives in shadows. He says, "But if you wanna go someplace where you and your family can have a future you can be proud of, to a brighter place where you can live with dignity, then... You must know no shame. Raise your heads and fight!" He says that they are lucky, and that they have people who want to do these things with them. Kouha says that his brothers En and Mei already took care of him, so now he'll take care of them. Then he asks if they're are any idiots who want to try and raise their stupid mugs.
At the age of 15, he was present in the treasure room of the 14th Dungeon, Leraje, with his brother, Kouen, and their subordinates who came to conquer the Dungeon. The Djinn, Leraje, told Kouha that if she was a normal Djinn, she wouldn't have chosen him, but the sexy guy standing on his side (Kouen). She says that Kouen is a cheater that already controls 3 Djinn, and she swore to stop falling in love with playboys like him. Kouha asks what she means, and adds that her make-up is shitty and she has the face of someone who was just left by her man. Leraje says shut up, and that she doesn't want to see a world that's ruled by a single and absolute king. She wants to see a king, and his strong retainers that wouldn't even lose to him, work together in order to build this world, this time. Kouha says it would be enough if he was just just a part of En's Household, but Leraje says no, and that he isn't fit to be the vessel for a Household. She says that she understood the kind of person Kouha was by looking at the eyes of his men.
When Judar arrives at Kou Empire's Army's Base in Balbadd, Kouha says that Judar is late and grabs his arm. He tells Judar that Balbadd is a sultry country and that he is really sweating. Judar says if that's the case, Kouha should get away from him, as Kouha is the one making Judar sultry. Koumei Ren appears and asks where Judar has been up till now, as they couldn't get in contact with him, and he was worried. Judar greets him and says that his gloomy face is the same as ever. Judar then gives Koumei a gift as an apology for his lateness. Koumei asks what it is and Judar says its a specialty from Sindria. Kouha is curious and asks his older brother to let him see it.
They go to meet Kouen Ren, who is in the throne room with the Left General, Kokuhyou Shuu, and the Right General, Seiryuu Ri, waiting for Judar to return. Kouen says for Judar to make him wait, he must've brought him an interesting present. Judar says he has, that he told Sinbad, "Why don't you fight a war, against us?" Kouha and Koumei are surprised that he did this without the Emperor's permission. Kouen starts laughing, and says that's very befitting for the Magi of his empire. Kouen tells everyone that for his empire that will rule the east, the day in which it will rule the world is imminent.
Kouha is on a caravan heading to Magnostadt with his attendants when Aladdin joins them. The caravan is then attacked by thieves using Magic Tools and before Aladdin could retaliate, Kouha jumps in front and starts to attack them with his Metal Vessel, Nyoi Rentou. He asks if they are trying to ruin the mood of his long-awaited journey. Kouha asks if he should execute the old men. One of his attendants says that they need to pass by unnoticed, but another one says it is useless. Kouha begins the onslaught by showing what Nyoi Rentou can do, which is elongate or retract at Kouha's will. He cuts the attacks from their Magic Tools, the thieves' hands, the horse's heads, and begins to slice the thieves and horses into pieces.
After the fight, back on the caravan, Kouha asks who the dirty brat, Aladdin, was. One of his attendants says Aladdin has been traveling with them for a while now. When Aladdin realizes that they are traveling to Magnostadt, Kouha informs Aladdin that only special exceptions like him and Magic Users can enter. Aladdin says he's a Magician and he's going there to study. The driver of Kouha's cart informs him that they will arrive in 9 days. Eight days later, Kouha dropped Aladdin off at the Magician's entrance into the capital. Kouha tells Aladdin that he will have someone pick him up there and wishes him good luck.
Soon after, during a diplomatic negotiation with Matal Mogamett, he is informed about the death of his father. Mogamett says that they are in a dire situation now and suggests that Kouha return home to the Kou Empire as soon as possible. Kouha agrees and says that the warning he gave Mogamett isn't a lie: "The Kou Empire will invade Magnostadt soon. Before that happens... choose between submission or destruction." When he is outside, Aladdin flies down to greet him. Kouha says its been a while since they've seen each other and wants to hang out, but his "pops" kinda died. Aladdin realizes that Kouha's father is the Emperor of the Kou Empire. Kouha says that he will leave things in the care of his attendants while he is gone. He adds that the next Emperor will obviously be his brother "En", and there isn't a single force left that can oppose the Kou Empire from inside it.
A day after he arrived in the Kou Empire, Kouha heads to the funeral with his siblings. There, Gyokuen Ren greets her children. Kouen asks if the Emperor died of an illness, Gyokuen says that he was ill for a long time, and it suddenly became worse. Kouha gets disgusted when Gyokuen grabs Kouen's arm and asks if he will support her, and calls him her most loved son. Kouha talks to Mei and says that Gyokuen always fawned over En, and now it seems she has finally decided to move on from him. He asks Mei if in that case they don't need to hear the testament, but he only says to Kouha mind his manners and look forward, since the priests will begin to read the testament. During the reading of the Emperor's will and testament, Kouha thinks that the next Emperor must be En, as everyone who has rights to the succession are under his command, except Hakuei Ren and Hakuryuu Ren. Kouha is surprised when the testament stated that the Third Emperor of the Kou Empire is Gyokuen Ren, and that she will be assisted by the Imperial Priests in tending all national affairs. An argument ensues and the tension starts to rise, until Hakuryuu bows to her and asks her to take the throne, and that no one but her can do it. The Imperial Priests start chanting that, which surprises Kouha, Hakuei, Kougyoku, and Seisyun Ri.
At the end of the day, he talks with his brothers about Al-Thamen. Kouha tells En that what happened in Magnostadt wasn't what they expected. When he was negotiating with them, even though Mogamett faltered when Kouha mentioned Gyokuen, the chancellor refused to collaborate. Mei mentions that Magnostadt is just like the Kou Empire was a few years ago, with their mass-production of Magic Tools, and the sudden development and increase in their military force. He suspects that Al-Thamen is behind it. En states that it is the result of their Magicians that they were able to expand their strength to that extent, and that if they would come to oppose the Kou Empire, they would be a frightening country.
Kouha is in the Tenzan Plateau when one of his subordinates, Meihou Kan, tells him that they received a message from his attendants in Magnostadt. He is told that the Reim Empire is going to invade Magnostadt. Kouha says that's a load of bull, and that Magnostadt doesn't belong to Reim, it belongs to his big bro. The subordinate asks Kouha if he will do something about it, and he says you betcha. He appears to be setting out to Magnostadt.
Some time later, Kouha and his vanguard are on their way to Magnostadt. His Magician Attendants call him and tell him that his hair gets messed up when he rides a horse. They asks if he would like to use a palanquin. He says no can do, as he was given a lot of soldiers, and if he wouldn't lead them, who would? He tells them that they've came a long way, so they shouldn't talk like carefree girls anymore, and they apologize.
Kouha says no biggie, and since they stayed in Magnostadt, they could give him tons of information. He tells the attendants (Jinjin, Junjun and Reirei), that they did a good job. They cling to him and ask to be praised and caressed like they always are, but he tells them to stop being so clingy, as his hair is a mess. He says if they want to play, do so after they win this battle. A male attendant says that their victory is certain, and for Kouha to leave everything to them, and that at any rate "those people" said that they would lend them their power. Kouha says that their is no need that this, as he will bring Magnostadt down with the vanguard alone. Meihou agrees and adds that no enemy is capable of opposing Kouha's Metal Vessel. Kouha agrees and says that he got this power by pure luck, but he feels like using it. Kouha says he really wonders how he got this thing, and that he really doesn't get those Djinn.
Kouha tells everyone let's go, as they're almost at Magnostadt. Kouha notices something in the sky and asks what it is. Just then, 3 Black Djinn fly toward the whole vanguard, and mercilessly attack everyone.
Kouha was fast enough to save a majority of his army, by stretching Nyoi Rentou to an enormous size. Junjun and a male member of the army call him, but he is distraught and angry for what the Black Djinn did. Kouha names some of the members of his army that got killed: Meisai, Meishin, Mouketsu, Ryobun, Teishuu, Koushou Ka. Kouha fully Djinn Equips Leraje, and says that he will kill the Black Djinn. He starts to slash one of the one of them multiple times. A member of the army states how the Black Djinn has been reduced to tiny pieces, but Kouha says that it isn't over yet. Everyone is surprised when the Black Djinn starts to regenerate.
Just then, a Metal Vessel Symbol appears above the 3 Black Djinn, it is Kouha's Extreme Magic, Lelazzo Madraga. Kouha slashes down on the Djinn, and everything in the vicinity gets pulverized by the sheer force of the Extreme Magic. The Djinn are all smashed into a crater in the ground, leaving just Black Rukh.
Kouha is obviously tired, and his Magician Attendants note that he is running out of Magoi, and say that they will give Kouha's Metal Vessel the 7th Type of Magic until they run out. As the male member of Kouha's army expressed his relief that the Black Djinn were annihilated, the Black Rukh leaves, which makes Kouha's Magician Attendants wonder their destination. After a while, an army of bigger Black Djinn appear.
They start to step on and kick Kouha's army. When they get to Kouha, he makes the size of his Djinn Equipped Nyoi Rentou grow, so that they couldn't attack those closest to Kouha. Kouha starts to tremble from the force of its weight, which causes his arm to break. Just as two other Black Djinn also step on Nyoi Rentou, they all mysteriously get slashed up. The person that saved him was Alibaba Saluja in his Full Djinn Equip form.
A soldier asks Kouha if he is an ally. Kouha says that he's a Metal Vessel user, and asks what he's doing here. Kouha sees Alibaba cutting the Black Djinn, and tells him that they'll regenerate, and they won't die if he just cuts him. Alibaba then changes the shape of his sword, and summons a lot of flame. Junjun talks about the heat, and Kouha calls it a flaming big sword. A member of Kouha's army exclaims that Alibaba burst through 3 Black Djinn in a single thrust. After he beat them, 30 more Black Djinn come. Kouha sees that Alibaba is about to summon his Extreme Magic. As he is about to attack, another attacks beats him to it. Kouha and his army see that it came from his Kouen and members of his Household. Kouha can't believe that he would show himself here. All of Kouha's army is glad to see him, but Kouha feels ashamed that he had to trouble Kouen. Reirei says that since Kouen and his Household are here, they should be safe. Kouen looks down to see Kouha, then tells his Household that if the enemy is too much for them, then they will deal with them with their strength.
Kouen's Household begins to destroy the Black Djinn in their respective ways, and Kouen comes to Kouha. Kouha asks Kouen for forgiveness, as he volunteered to take the vanguard. He says he caused a great loss, as the war is really important for advancement toward the west. Silently, Kouen pulls out his sword. He points it toward Kouha, which surprises Junjun. Kouen uses the power of his Djinn, Phenex, to heal Kouha's broken arm. Kouha and his attendants are very grateful that Kouen healed him. Kouen takes command of the army.
Later, after the Black Djinn disappear, Aladdin and Alibaba are in front of the Kou Army. Alibaba introduces himself as the prince of Balbadd. Kouha is worried about Aladdin. The people of the army figure out that he must be a protégé of Sindria, so he could be an enemy. Alibaba walks right up to Kouen and says, "I stepped on the battlefield in order to protect the life of the third Prince of the Kou Empire, Kouha Ren." This surprises Kouha. The army wonders if this is true. Junjun tells Kouha that he is telling the truth, and says he's a good person. After Kouen's long period of silence, he asks Alibaba if he's looking down on him since Alibaba has already lost his country. This breaks Alibaba's spirit, but then Kouen thanks Alibaba and says he did a good job saving Kouha.
Suddenly, the sky turns black, and Aladdin seems worried. He gets Kouen's attention by calling him, "Old Man Kouen", which surprises everyone, and begs him to send back his soldiers. He says that it doesn't matter if they're from Kou or Reim, if the people around here continue to fight, they will die. Junjun and Reirei comment on how Aladdin seems different from the first time they met. Reirei says he isn't wielding a staff, and he clearly didn't use any magic in front of them, and yet something if different about his rukh. Aladdin says they don't have time and summons Kouen's 3 Djinn.
Then, Aladdin calls out Kouha's Djinn, Leraje, and Alibaba's Djinn, Amon. The Djinn ask if Aladdin called them, and call him Magi. They realize that Aladdin is the "Fourth Magi". Amon tells everyone that they have to close the "dark spot", or else the world will be annihilated. He explains that a "hole" has been opened, and that from there, the incarnation of evil will descend upon them. He says that anything it touches will have the White Rukh inside of their body stolen and erased. Leraje tells them not to let the world die or it'll end up like "Alma Torran". Astaroth, one of Kouen's Djinn, stops her, and says that the humans of this world shouldn't even know the existence of the "other world".
This sparks Kouen's and Kouha's interest. Alibaba asks Amon what they should do to stop the world from ending. Amon says they have to destroy the "Medium". He says that "Ill Ilah", is the incarnation of evil and a high order being from another dimension. He says the trigger to bring it to this world is the "Medium", the crystallized body of an immense quantity of Black Rukh and Magoi. He adds that this is the final objective of Al-Thamen, and the reason they are causing the world abnormalities. Aladdin asks if they just need to defeat, and Amon says yes, but it will be a difficult fight even considering Aladdin, "Solomon's Proxy" will be there.
Kouen goes up to Aladdin, grabs him, and asks him questions about Alma Torran. Aladdin says if Kouen send back his soldiers, and helps destroy the "Medium", he'll tell Kouen everything. Kouen agrees and calls forth Koumei, Hakuryuu, Hakuei, and Kougyoku (which is done by using Long Range Clairvoyance Magic, as explained by Junjun later on). Kouha asks if Kouen's gonna believe this absurd story. Kouen says if he would be able to solve the mystery of this world before uniting it, then from now on there won't be any need to repeat the thousands of wars that happened in the other world. Kouen tells Aladdin that he will lend him the power of all the Metal Vessel users in the Kou Empire, and in exchange for this, after this is through, Aladdin will tell Kouen the truth about this world. Koumei, Hakuei, and Kougyoku respond. They all Djinn Equip, their Djinn say they leave everything to them, and then set out for Magnostadt following Aladdin.
Kouha appears on the battlefield with Kouen, Koumei, Hakuei and Kougyoku. He defeats one of the Black Djinn alongside Kougyoku. When Kougyoku is noticed by Alibaba and is happy to see him, Kouha, astonished, reminds her that she's talking to an enemy's general and asks her why is she so over-familiar with him. She explains to him that they're good friends. Then, like others, he faces an overwhelming number of enemies.
He fights alongside Kougyoku. He curses that he can't even land a killing blow unless he slashes them to ribbons. Tired, he comments that the Black Djinn are coming and coming. He asks Aladdin what they should do. Aladdin explains that it's living creature and everything it does are the acts of Magic, so its Magoi is consumed. He says that when production of Black Djinn will make it run out of Magoi, its defensive wall will disappear and they will be able to defeat it. Kouha replies that he understands and asks how many more Djinn will pop out before their enemy will exhaust all of its strength. When Aladdin answers that around ten thousand, Kouha looks very shocked. Then, he comments that they won't make it with their Magoi. He then surprised notices that Kouen started to move.
Afterwards, when Kouen shows his scary side during his fight, Kouha explains to Aladdin and Alibaba that his brother En always thinks about their country, but in private he's a person greedy for knowledge. He notes that right now, all Kouen is thinking is that conversation he's gonna have with Aladdin and says that he's pissed off now. When Kouen grabs Alibaba and wants his support, Kouha is surprised and wonders what Kouen is up to. Much to his shock, the two of them want to activate their Extreme Magic at the same time. Kouha says that he has never seen it. He then watches Alibaba and Kouen destroying the defensive wall.
When Koumei begins to complain that transferring potential damages from the city is quite exhausting, Kouha cheers him up telling him to do his best. When the Medium begins to absorb the Black Djinn, Kouha comments that first it spit them out and now chews them back again and adds that it sure knows how to keeps itself busy. When Aladdin, terrified, exclaims to not let the changed Medium near the city, Kouha asks him what's wrong. Upon hearing that once touched by the palm of its hands, no matter what it is, its Magoi will be taken and it will die, he responds, appalled. Kouha is shocked when he sees that Kougyoku was able to spear the Medium.
Kouen orders Koumei to direct the rest of his siblings. Koumei calls their name, to what Kouha, along Kougyoku and Hakuei, answers "Yes!". Kouha uses his Extreme Magic, Lelazzo Madraga and creates a hole in the enemy which Kougyoku and Aladdin make bigger. It isn't enough to win. Kouha comments that even with their Extreme Magic, but whatever they do, the Magoi is not enough. Kouha then uses one of his attacks, which, alongside everyone else's attacks, is transported and combined with other's moves through Koumei's Dante Al-Thais. Kouha then, completely worn out, watches what happens, but the Medium takes sea's Magoi and becomes bigger.
Kouha asks if they really can win against the Medium, as they can't use their Extreme Magic anymore and their Djinn Equip is at its limit as well. When Kougyoku gets caught in the Medium's hand, Kouha cuts its arm and screams that he isn't gonna let it kill one of his family. However, he also is caught in the Medium's hands and while Kougyoku suffers only from legs' injury, Kouha's whole body's skin is tore off with him very heavily bleeding.
He is then carried around by Koumei, until he regains his Magoi thanks Scheherazade. He Djinn Equips and alongside other Seven Seas Alliance's member as well as Reim's and Kou's Dungeon Capturers, uses his Extreme Magic to deliver the final blow to the Medium.
He then watches the Medium falling to pieces, hurt and exhausted. His Djinn Equip wears off and he falls on his knees. When the Medium begins to hesitate, Aladdin goes inside it by using Wisdom of Solomon. After his success, he watches the Medium's destruction. When Kouen stands against Sinbad, Kouha has a serious look on his face. During Sinbad's declaration that he had to use all the power he had to return Magnostadt to its former glory, Kouha realizes that Sinbad wants to seize it all for himself. He is surprised when Kouen wants to take Aladdin with him. He comes to him and asks him if he's going. When Alibaba comes to take Aladdin and orders him to get his hands off Aladdin, Kouha argues that Aladdin doesn't belong to him.
Kouha is seen in Aladdin's flashback, when he, his family and allies leave Magnostadt riding a carpet.
In Balbadd, Kougyoku reveals to Alibaba that Kouha and Hakuei are watching over Magnostadt's "abnormality" from the Tenzan Plateau.
When news of Judar and Hakuryuu's uprising reaches the Empire, Kouha is at first shocked and then angered, calling Judar by his name before pausing for a moment and then changing his title to "priest". Even after being briefed on the situation, he still can't believe what was happening.
As Kouha and his army prepare themselves for battle against Hakuryuu, Kouha with his determination steeled, vowed that this fight would be "the last fight in the Kou Empire's history" and telling his army that they were going to finish it. His handmaidens look at him worryingly as they continue to advance.
He has been shown to be a skilled swordsman using his metal vessel skillfully to dispose of a bunch of thieves.
Leraje is the Strength Djinn that Kouha received after he captured the 14th Dungeon. Kouha's Metal Vessel is a big sword he carries with him. His Metal Vessel seems to able to gain power from other Strength Magic users to recover its Magoi and strength.
- Nyoi Rentou (Refined Blade At Will): Nyoi Rentou seems to be able to cut anything. In addition, Nyoi Rentou can change its length, becoming very heavy and difficult for its owner to use. Kouha uses this power only in the precise moment that he needs it.
- Djinn Weapon Equip: When equipped the sword becomes a scythe on one side and a hammer on the other. The Scythe side can be used to create swift slashes that are capable of traveling to certain distances. The Hammer side can be used to apply great pressure to a certain region. It still retains its ability to change size at will.
- Djinn Equip: In this form, Kouha's hair grows longer and its color changes to light purple. He has pink spikes coming out of his back that take the shape of wings. He gains a sideways third eye in the middle of his forehead. His arms and legs are both become clad in the same spikes which take the shape of armor. He wears a necklace and arm bracelets on both arms.
|“||Engrave her cruelty, disappear under queen's crushing grief!||”|
—Kouha's Extreme Magic Chant
- Lelazzo Madraga (Refined Hammer At Will): When in Djinn Equip, Nyoi Rentou changes its shape and becomes a scythe, and the opposite side of its blade is flat, resembling a hammer. Kouha hits with this side with an enormous power, that disintegrates everything its blast touches.
|Quantity of Magoi||
Kouen is Kouha's older half-brother. Kouha respects him very much. He considers Kouen a dignified person, and doesn't wish to give trouble to him. He conquers other countries in attempts to make Kouen the Emperor. Also, when he talks about or to him Kouha changes his way of speaking, and abandons his casual tone to a quite dignified way of speech. However, Kouha usually refers to Kouen as "En-nii", an informal way to say "brother En".
Both Kouha and Koumei show a high respect for Kouen and they also know very well Kouen's greedy of knowledge side.
Koumei is Kouha's caring and responsible older half-brother. Despite having different birth-mothers, their relationship is a pretty good one, since there are many occasions where they have worked together. Koumei often saves Kouha from the naive things he does and defends him in battles. He worries about the well-being of his little brother.
Kouha has a strong bond with his army. He personally recruited all of them, who were the repudiated of the world. He encouraged them, and told them not to be ashamed of who they were. In return for that, his army loves and respects him greatly, and considers him their king.
Kouha cares of them greatly, and it's been seen when Kouha protects his army from Mogamett's Black Djinn, and how he gets infuriated when some of them die. More proof is that he seems to know every one of them by their names.
Kouha and Aladdin were traveling on the same carriage when Aladdin wanted to go to Magnostadt. They seem to get along together. Despite Aladdin's reveal as the fourth Magi, Kouha does not seem to be bothered by the fact and is still on good terms with him.
Kouha seemed to get along with Judar and considered him to be a friend. When he and his brothers discover Judar's treachery in helping Hakuryuu, he is visibly shocked and angered; even momentarily calling Judar by his name before quickly changing it to "priest".
Although they have different statuses, Kouha seems to care a lot for Kougyoku, and protects her in battle. When she becomes scared in battle for killing the enemies who were once Kou soldiers, Kouha encourages her to fight because it was the Ren family's responsibility; adding if they hesitated for a moment, many of their enemies and allies would die due to that hesitation. Kougyoku even refers to Kouha as "brother". He also becomes protective of her when he realizes how close she is to Alibaba. They seem to be closer to each other than to their other siblings, despite having different mothers.
- His name means Crimson Supremacy in Japanese and Crimson Tyrant in Chinese. needs ref
- "Kouha" is the Japanese pronunciation; in Chinese his name would be Hóngbà.
- He is the same age as his sister Kougyoku.
- His specialty is hacking things to pieces.
- His hobby is beautification and fashion.
- His favorite food is fig and he dislikes spicy food.
- His type of woman is an individual and he dislikes people that don’t do anything of their own accord.
- His favorite way to spend a day off is appreciating his subordinates.
- He is worried about his mother.
- His weaknesses are his brothers.
- He has a complex because his mother is different from his older brothers; he thinks it's a slight weakness.
- He often teases Koumei about his looks, calling him "ugly" on the one hand but handsome on the other.
- When it comes to dealing with woman, Kouha is even better than Sinbad or Aladdin.
- Interestingly enough, he was chosen by Leraje because she thought Kouen was a cheater (as he already had three Djinn) and because of the way Kouha treats his subordinates, demonstrating his leadership qualities.