The leader of the gang Ragnarok, and thus one of the major antagonists of the History's Mightiest Disciple series. Also a childhood friend of Kenichi.
Ryuto Asamiya was the first friend Kenichi made. Ryuto was the only kid who was shorter, weaker and kinder than Kenichi. However, Ryuto wasn't above using his friends as whenever they played hero and villain he would always take the hero role and leave the villain role and when he would get a cat pin that he did not like he would force Kenichi to take it, thought according to Ryuto himself Kenichi wanted the cat pin.
At that time a young Miu would come and ask the two of them how to use the machine to buy a pin. When Miu got the yin yang pin she started to cry and says that she wanted a cat pin. Hearing this Kenichi traded Ryuto cat pin for the yin yang pin making Miu happy and smile which made both Ryuto and Kenichi blush.
After that three thugs tried to steal the store that Kenichi, Ryuto and Miu got the pins from. Miu would fight and take down the thugs all by herself in front of Kenichi and Ryuto. While Kenichi kept his eyes closed Ryuto could not take his eyes off the scene and was amazed by how Miu could take the thugs down without breaking a sweat. While Miu was talking to the old lady in the store one of the thugs tried to sneak behind her with a knife. However, Kenichi made a sound which caused Miu to notice that thug and take him down. Kenichi was hit by a bottle on the head and Ryuto would try to wake him up while Miu went and brought her grandfather.
Seeing Ryuto trying to wake Kenichi she believed that it was Ryuto who made the sound and thanked him. Later, while setting in the park Ryuto would want the yin yang pin that Kenichi traded the cat pin for it saying that the cat pin was his in the first place. Kenichi would refuse and the two would fight while putting the pin as the prize for the winner. Kenichi would win the fight put would try to give the victory and the pin to Ryuto and says they should pretend that Ryuto won the fight. Ryuto would respond unkindly to this and start to hate his friend. That night Ryuto would return to the store and buy all the pins there until he got yin yang pin, but he would feel only emptiness and realized that it wasn't the pin that he wanted it was what the pin meant and that was the victory. The two would make a promise to be strong as Miu and when they do they would fight for the honor of wearing the yin yang pin.
However, when Kenichi family moved from town Ryuto would run behind the car to remind Kenichi of their promis, but because of the noise of the engine and Kenichi father driving faster Kenichi could not hear what Ryuto was saying and only told his friend goodbye which caused their friendship to break. Ryuto would absorb himself into martial art and start to practice in order to gain power so he can win the fight when he meet Kenichi again and take the pin.
However, Ryuto would always feel that his level is not the level he wanted and slowly changed as he started to walk the path of asura. Ryuto would be disqualified due to savagely beating an unconscious opponent during a tournament. While wondering how he could be disqualified and the one who was unconscious on the ground won he decided that he need to find something else to practice. At that time he would see Ogata defeat and kill two armed opponents. Seeing this Ryuto felt a shivering down his spine, but he knew that it was not caused by fear and ran to Ogata to ask him why did he killed him opponents. After hearing Ogata answer Ryuto realized that he finally found what he was looking for.
Ryuto became the disciple of Ogata who would train him in the mountains and Ryuto would successfully awaken his Ki of Dou. Ryuto would fight Berserker and win. The later would become the former right hand when Ryuto started to build Ragnarok. After building Ragnarok Ryuto would come across Rimi who challenged and defeated the leader of the Titans and claimed the position of the leadership, but the others member of the Titans didn't accepted her and tried to attack. Ryuto seeing this claimed that they are weakling and defeat them all and stated that Rimi would have won without his help, but would have sustained an injury that wouldn't completely heal. Ryuto told Rimi that she is strong and he like strong people. Unknown to Ryuto, he gained Rimi affection and love. After his master exiled himself into the mountains Ryuto start to gather more minions to prepare for the war against Yomi.
Ryuto would first appear as a shadowy figure along the other members of the seven fist of Ragnarok who became the eight fist of Ragnarok after Kisara joined them to test her skill by making her deal with 50 member of a rival gang while backed up by Hermit and Loki. After that he fully appear while discussing the mater of the Shinbaku Alliance with the other fists, where Loki says he will deal with the alliance.
After the defeat of Siegfried and the failure of Loki plan, Ryuto appear to be amused by this, but after hearing that their opponent was non other than his old friend Kenichi himself he was shocked and start to wonder if it was really Kenichi. Later, while observing a fight with the other fists he tell Kisara that he had a change of heart and remove the punishment that was put on her as the defeat of her team wad punishment enough. Then he start to wonder if it was really Kenichi who is leading the Shimbaku Alliance then he can finally fulfil the promise they made long time ago all while ignoring the fight everyone else was looking at and staring at the yin yang pin he felt emptiness after getting it. After witnessing Hermit return he agreed to let him handle Kenichi despite the objections of Loki.
Ryuto would appear after Loki, who kidnapped Honoka and tricked Hermit into believing that Ogata was the one who gave the order for Loki to be the one to handle Kenichi, and stopped Loki fight with his old friend and caused Loki to flee after threatening him if he ever do something like this again. After that he tried to convince Hermit to return to Ragnarok, but fail and tell his former subordinate that the next time they meat they will be enemies. Before leaving he tell his old friend that he will fulfil their promise soon all while he knows that Kenichi don't remember and staring at Kenichi yin yang pin.
Later, Ryuto appear to Kenichi when he returned to his home town in order to remember his past and while Kenichi remember him only as the first fist and was ready for a fight Ryuto assured him that he is not their to fight him as he is not wearing his Ragnarok gloves. This caused Kenichi to calm down despite Miu warning. Ryuto start to talk about the past and how the store and even the old lady have not changed despite all that time and start to laugh with Kenichi. Ryuto tell Kenichi that he didn't know it was him at first until he saw his pin and with a change expression he tell his old friend that he is glad that Kenichi remember their promise and they should start as the park on the other side of the street is a perfect place for them.
However, Kenichi who still don't remember ask what are they going to do which anger Ryuto who ask if Kenichi remember what his name is, to which Kenichi admit that he doesn't remember. More angry than before Ryuto by a whole box of snacks and when he open one of the snacks by pressing it against his leg and eat it Kenichi finally remember his old friend. While remembering the past Kenichi remember the promise of becoming as strong as Miu, but don't remember the promise about the pin. Kenichi reveal to Ryuto that Miu is the same girl that they meat long time ago and that he is living at the same dojo she lives in. Once again Ryuto expression changes and he ask Kenichi what martial arts mean to him and after hearing the answer Ryuto seems to be disappointed with the answer. Kenichi ask his old friend to stop the meaningless fight between the Alliance and Ragnarok, but Ryuto respond by telling him that there is no meaningless fight and each fight has a meaning and that is to prove one supremacy over the other and Kenichi himself made the promise to make himself stronger. Kenichi ask Ryuto once again as the first fist to stop the fight between their groups.
However, Ryuto repeat his words and put on his gloves and tell his old friend that the answer is no and he will carry on the real promise that Kenichi has forgotten. Going to the park Kenichi who forgotten about the the pin promise ask if the promise Ryuto talking about is them fighting which Ryuto says it is and if he won he will take the yin yang pin from Kenichi much his old friend surprise. When they started the fight Kenichi held back which caused him to be thrown. Ryuto start to insult Kenichi sohe would not hold back and when this work Ryuto use his killing intent to pressure Kenichi and start to insult him again, but this time he uses his finishing move and tell his opponent that he doesn't go easy on anyone whether they were his friends or foes.
As Miu rush to Kenichi, who fall to the ground, side Ryuto tell her that a weakling like Kenichi doesn't suit her at all, indicating that Ryuto had crush on Miu ever since he meet her 10 years ago. However, Miu who doesn't return his feeling tell him that he hasn't seen Kenichi true power yet. At the same moment Ryuto feel a strong Ki coming from Kenichi as he sees him getting up, but after seeing him suffering from the effect of his finishing move he dismissed what he felt as mere imagination as the strong Ki he felt before has been replaced with a Ki that is not strong enough. The two continue to fight, but despite the determination of Kenichi he is unable to touch Ryuto who answer his question about this by telling him about the Seikuken. Kenichi try to use his finishing move, but due to Ryuto Seikuken it didn't work and Ryuto win the fight and take the yin yang pin from Kenichi and when he's asked by Miu why does he want the pin that much, Ryuto says that it has nothing to do with the pin as Kenichi did something to him ten years ago that is unforgivable and he wanted to have revenge on Kenichi. Ryuto take out the pin he had for the ten years, bind it and tell Kenichi that this is the meddle of a loser while throwing it at him. Ryuto state that he thought it was okay to keep Kenichi organisations around when he heard about it, but now he changed his mind and he will destroy it and leave while laughing at Kenichi. After this Ragnarok started to move in order to destroy the Alliance.
Later, Ryuto appeared next to Berserker when they came to check on Loki. Ryuto express his disapproval of Loki tactics and call it useless. This caused Loki to reveal his scheme to take over earlier than he wanted and announced that the new leader for the new Ragnarok is Berserker. However, Ryuto already knew about Loki plan and ordered Berserker to pretend and since the time has come Berserker defeated the so called new Ragnarok and Loki. After that Ryuto ordered the members of Ragnarok to surround the members of the Shinpaku Alliance. Hermit who was targeting Loki was enraged when he saw his prey being defeated by another fighter, Ryuto allowed Berserker to fight Hermit. The former seventh fist Thor, who joined the Allianc, tried to attack Ryuto in order to make an opening for the others to escape, but Ryuto easily strike a blow that weaken his opponent and when it was clear that Thor will not move away Ryuto was willing to use the same strike and it will kill Thor for sure.
However, the elder who was carrying Kenichi dropped him in the middle of the battle surprising everyone even Ryuto which saved Thor from a current death. After seeing what is happening and being informed by the other of what happened to the others, Kenichi demand to know if it was his doing, but Ryuto calmly responded by telling his former friend: "why would I personally go take care of these minor things?". Berserker revealed that it was him, an enraged Kenichi attacked him and after that used his newly learned Seikuken much to Ryuto surprised. Ryuto declined Kenichi request for a rematch as he already defeated him and stated that Berserker can handle Both of him and Hermit. However, Hermit decided to fight Berserker on his own. Both sides halted their fighting and started to watch Berserker and Hermit fight.
Ryuto sat back and watched the fight while making comments. After the defeat of Berserker and Kenichi trying to convince him that it's okay to be defeated once or twice as there are many people in the world who can defeat him seemed to work and Berserker saying that he was defeated before at the hand of Odin, the nickname of Ryuto in Ragnarok, and Kenichi should not fight him as it impossible to defeat him, Ryuto angrily strike Berserker and tell Kenichi that he should stop pretending to pity the defeated and fighting is a holy act where the winner walk over the loser. Kenichi tell his old friend that he do not know when he became like this, but he know now that he need to use violence to get to his twisted mind and bring him back.
Ryuto not impressed by Kenichi words tell him that he will never get throw his Seikuken. Kenichi attack only to nearly get hurt, but then remember to calm down in order to use the Seikuken which he does and set up his Seikuken much to Ryuto surprised. Both start to get closer to each other and start to attack. Ogata, who decided to end his exile, arrive to watch the battle of his disciple. However, due to his advanced experience with the Seikuken Ryuto gain the upper hand and almost win, but remembering the elder advice Kenichi managed to grab Ryuto and throw down, thought it was revealed that Kenichi only thrown Ryuto jacket and Ryuto almost attacked him from behind which Kenichi dogged it.
Ryuto tell his former friend to struggle all he want and he will make him feel helplessness. Kenichi ask him former friend to know why he changed as he was always the nice one and always had a smile on his face. Ryuto smile and coldly answer his old friend that it a simple mater of principle as the normal people can be swept down the stream while the strongest can move up the stream and Kenichi should feel happy as their promise to become stronger allowed him to build his Ragnarok empire. Ryuto ask Kenichi why does he strive for power and Kenichi answer with his usual answer that he want to protect the people he cares about and enforce his idles.
Ryuto who is unimpressed with Kenichi answer call him a deceptive which Niijima object on and says that Kenichi is an idiot who don't know how to lie and he is what he said he is and not. Ryuto once again not impressed he tell the others to get rid of the members of Shimpaku Alliance. Ryuto throw Kenichi away and tell him that it's clear that his motivation is wrong as his moves became slower after seeing his friends in trouble. When Hermit was about to get hurt Ryuto tell Kenichi that he can't protect anyone. However, the table get turned around with the arrival of Siegfried and the other members of the Shimpaku Alliance. Thought surprised at first, Ryuto dismiss them as small fries that he will deal with them all after he defeat Kenichi, but this make Kenichi angry who tell his former friend that his friends are not small fries.
After hearing Siegfried and the others speech about how Kenichi changed them, Ryuto call their speech as boring as hell, which Kenichi state that it's because he doesn't understand friendship. Ryuto angrily charge at Kenichi while tasking him how can he understand something that doesn't exists. Kenichi use the first technique he learned from Miu to make Ryuto fall. Kenichi tell Ryuto to take off his glasses as he is about to bind his twisted personality back into its place, but he doesn't want to him to be blind. Ryuto laugh and ask Kenichi if he really want to him to take off his glasses and tell him that once he take it off his body will feel why they gave him the nickname Odin.
Kenichi try to charge at Ryuto, but Ryuto easily dogged and attacked much to Kenichi surprise. Kenichi try to attack, but all of his attacks are blocked and before Kenichi even attack Ryuto saw throw it and attacked first. Ryuto tell his former friend that there are things that seem to be clearer if one don't look at it, Kenichi masters realize that Ryuto have mastered the inner eye skill. Kenichi try to raise his attack speed, but still there is no affect and Ryuto tell him that if it was someone else he would have won, but he is facing him it's useless because of his perfect Seikuke his attacks will hit nothing but air. After telling Kenichi that his attacks are repetitive, Ryuto start to attack using a technique called Gungir that never misses its target. After asking Kenichi how does it feel to be hit by Gungir Ryuto recall that they used go to the same abandoned factory they are fighting in it currently to play heroes and Kenichi confirm it and says that every time they play Ryuto choose to play the hero while he is left to play the villain role. Ryuto laugh and tell Kenichi that today he will give him the chance to reverse the roles.
After remembering and recalling how he got his yin yang pin and seeing Miu taking down three thugs all by herself, he tell his old friend that since that day he knew he wanted to become a martial artist like her and absorbed himself into the martial arts he thought Kenichi would take up martial arts immediately like him, but he didn't and strike him. Ryuto then ask if this was all Kenichi had and mock him by asking him to use some of his true strength. Ryuto then start to talks about strength and how amazing it is as it can gather, force people to obey and even destroy them and raw power can be considered an art. Matsui try to help Kenichi, but Ryuto easily dogged his attack. However, Ryuto drop the yin yang pin which Matsui pick, seeing that Ryuto goes all out and attack Matsui and pick the pin after being dropped.
Ryuto then says that wining or losing depending on how much power and techniques one accumulated before the fight, but the losers weren't born with the talent and ask Kenichi why would he pity such people. Kenichi answer Ryuto that because there are people like him who strike down people who want to live peacefully. Ryuto hearing this wonder how could they have different view of the way of things despite witnessing the same thing when they were younger and tell Kenichi that he followed the wrong mastets which anger Kenichi and his masters much to Ogata amusement. Hearing Kenichi defending his master Ryuto tell him if his master was present he would tell him that he should put aside these feelings and he is incredible and has true power. Ryuto then recall how he meet his master.