Tirawit Kokin is a member of Yomi, a Muay Boran (Ancient Muay Thai) practitioner, and the disciple of Agaard Jum Sai and the holder of the Flame symbol of Yomi His nickname is Narasimha, which translates to "Lion God King".
Tirawit is Thai with dark colored skin and tribal tattoos over his face. He also has blonde hair and has eyes with black sclera and red irises. Tirawit is often shown wearing a formal dress suit. He is also quite handsome, garnering the affection of many high school girls, some who stare at him as he walks past. He shares many traits with Natsu Tanimoto: the hairstyle, hair color, body build, and even the cold, rational personality.
Tirawit is a calm individual and likes to plan ahead. He is also incredibly intelligent as he can make a 100% correct analysis of a person quickly. This is likely his default personality even when training, as even his master has only seen him while he was calm, and was surprised that he was fighting with anger because Agaard presumably tied with Apachai.
Tirawit also is a master of mind games, as he easily manipulated Kenichi into recklessly fighting him. His calm and calculating nature puts him as one of the strongest members of YOMI and a ruthless fighter, putting Kenichi on the defense for nearly the entire first fight.
He has also shown to be an expert teacher, as he managed to teach an entire karate club Muay Boran attacks with enough ferocity to catch Kenichi off guard, though he only taught them offensive moves. This likely stems from his experience with Agaard.
While a very serious person, Tirawit is capable of showing humor when finding something amusing, such as when Kenichi proclaimed he would end the fight with him using only Muay Thai, Tirawit was unable to control himself and burst into laughter at the thought, stating he couldn't even read his movements.
Tirawit has been shown as one of the most calculating and ruthless fighters that Yomi has. It is revealed as Tirawit fights in Dou combat that he has been taught to "attack his enemy's attacks", as opposed to simply defending against them. As
a result, his ability to counter his opponents' moves is incredibly high, able to dish a counter to Kenichi's Korui Nuki while being hit, diverting some of the attack's power to Kenichi and standing up calmly after being launched.
- Thai Kickboxer: Tirawit specializes in the use of both Muay Thai and Muay Boran, as a result he is well-versed in both the modern fighting styles of Muay Thai along with the ancient fighting techniques and teachings associated with Muay Boran. Because of this, Tirawit is an incredibly versatile fighter who can overwhelm his opponents with the strength and force of his techniques. Tirawit has proven how lethal his attacks can be, as he kept Kenichi on defence for most of their fight and was seen stopping Kenichi's heart with one attack during their first encounter. In their second fight, he was able keep ahead of Kenichi most of the time and counter most of the latter's attacks despite him resorting to using all six of his martial arts style.
- Master Analyst: He is well known for making perfect calculations on people and their abilities in a matter of moments. When analysing Daimonji, he simply stared into his eyes and measured his pulse. However, against Kenichi, he analysed his profile by more physical means, wrestling with him in a contest of strength during the school festival. In his second battle against Kenichi, he quickly deduced how the Ryūsui Seikūken works and Satomi Kajima also stated that a mistake in an analysis from Tirawit is exceedingly rare.
- Master Strategist: Kokin is a master manipulator in and out of combat. He uses a psychological attack by stating that Kenichi was the one that assaulted his minions, and also remarks that the damage done by Kenichi's fists is similar to the Satsujinken path he follows, evidenced by the fact he beat his classmates so badly, which easily provokes Kenichi into making a reckless attack. Even in their second fight together, he is able to trick Kenichi again to lose his temper.
- Expert Teacher: Tirawit has been shown to be a very good teacher. He was able to teach the Karate Club in the art of Muay Thai that through coordinated attacks were able corner Kenichi enough to force the latter into resorting to use the level of strength usually reserved for YOMI members like Kokin himself to stop them and unintentionally knocked them out.
- Enhanced Strength: He is able to send Alan Subishi into a coma with one knee strike to the torso, knock a punching bag hanging on a chain across the room with one punch, and penetrate through Kenichi's Seikūken using nothing but brute strength through an elbow strike. This makes him physically stronger than Kenichi, who has undergone intensive strength training through Ryōzanpaku. Tirawit was also able push back Takeda when the latter grabbed his uniform collar with nothing but a finger flick that left Takeda visibly shaken despite the boxer having undergone intensive strength training under James Shiba like Kenichi. He even managed to push back Marmaduke Brown's disciple with a knee strike despite him/her donning knight armor and defending with their shield and was able to damage the shield itself.
- Enhanced Speed: He has yet to demonstrate anything special, but the fact that he is able to keep up with Kenichi during their fights shows that he has at least a decent amount of speed considering that the latter became fast enough to catch up to a speeding truck.
- Strong Heart: It was revealed by Kajima that Tirawit has a more powerful heart than his own, and that he has beaten Kajima at chess several times because of his heart, since, as Tanimoto said, "First Guts (Heart), Second Power, Third Kung-Fu (Technique)".
- Enhanced Endurance: Kokin has demonstrated an incredible amount of stamina, being able to take Kenichi's Mubyōshi and keep fighting as if it didn't affect him, a noteworthy feat as even someone as strong as Shō Kanō fell after taking the blow. Even after taking Kenichi's Korui Nuki, a move that the Elder states can defeat a disciple or an expert level opponent, he was able to stand up and keep his calm disposition which Kenichi state was impossible to be fine after taking that blow (however, Kokin managed to stand up due to him kicking Kenichi in the back to lessen the blow of the kick).
Tirawit is one of the five YOMI members transferred into Kenichi's high school, quickly taking control of the school's karate club and teaching them
Muay Boran techniques. This accomplishment was marred by the fact that he willingly withheld teaching them any defensive techniques, allowing Kenichi's attacks to do maximum damage. The fact that his underlings were defeated so easily was part of his plan - he taunts Kenichi, stating, "It's been a long time since you fought a regular person."
Throughout their duel, Tirawit makes use of even his unconscious minions, throwing them in Kenichi's way as he attacks. Tirawit drops his guard, knowing full well that Kenichi will hold back due to both his gentle nature and fear of hurting another person (his fear being amplified by Tirawit's psychological attacks). In this moment of hesitation, Tirawit strikes Kenichi with Yan Erawan, smashing his knee directly into his heart. With a single connected strike, Tirawit places Kenichi into a near-death state, and responds to news of his apparent failure to kill Ryouzanpaku's disciple with the fact that Kenichi has died as a martial artist.
Tirawit has said more than once that despite Kenichi defeating Shō Kanō, who was both the leader of Yomi and easily one of its strongest members, Kenichi would still need more experience in battle before facing him, indicating he is a much more powerful opponent.
After causing what he thought was Kenichi's end and communicating it to Kajima Satomi, he transfers schools. When he is informed of his failure to destroy Kenichi's heart by Kajima, he attempts to set off to deal with him again. Kajima promptly forbids him from engaging Kenichi just yet, explaining that Tirawit needs to let the other members of YOMI have their "turns" first.
Tirawit fights Kenichi in the Okinawa Yami base while his master Agaard Jum Sai fights against Kenichi's master Apachai Hopachai. He taunts Kenichi for using defensive moves and calls him a coward, inducing a rage in Kenichi that prompts the latter to fight for revenge. Tirawit's attacking moves mirror those of his master at simultaneous points.
Initially assuming that his master won and waiting for Kenichi to finish mourning for Apachai, Tirawit is shocked
to see his master fall to the ground and proclaim the match a draw. He flies into a rage at this and resumes his match with Kenichi, with both of them attacking each other in Dou combat and countering each others' moves. He counters
Kenichi's Korui Nuki while taking the brunt of the attack. Unlike Kenichi, Tirawit does not seem fazed from the attack. When Kenichi states that he will finish the battle with only Muay Thai, Tirawit laughs and proclaims that he does not bear ill will towards his opponent. Tirawit analyzes him once more whilst preparing for his final attack. However, he miscalculates and is hit by Kenichi's punch and kick.
I have read all your moves but that one...magnificent, Shirahama. - Tirawit upon being defeated by Kenichi. Tirawit subsequently apologizes to his master, who affirms that he bears no ill will towards his disciple and compliments him for the fight. It is assumed from Tirawit's lack of action upon the Bantou master's intrusion that he has subsequently passed out or chose to remain quiet in order to avoid being killed. In the aftermath of the Okinawa Arc, both Tirawit and his master were deported to Thailand.
Following the beginning of the Eternal Sunset, Kokin reunited with his fellow Yomi members (minus Sho and Jihan) as they prepared to fight in the upcoming battles. Kokin further taunts the weapon users and the Yomi face off and prepare to fight each other. The fight is broken off by Kajima who tells them to save it for the enemy. He was later seen gathered with the rest of Yomi led by Kajima as they prepare for battle.
He was later seen with the rest of YOMI (minus Kajima) facing the Shinpaku Alliance. After Kenichi, Miu and Niijima escape, he and the other disciples charge the Shinpaku Alliance.
However, Kokin and the other unarmed YOMI disciples remain on the sidelines during the ensuring battle. After Chikage's assault on the armed division's lack of honor and ganging up on the Shinpaku Alliance, Kokin allies with the alliance temporarily. He then attacks Marmaduke's disciple and then Kokin talks to his master and asks for instructions on what to do "for the pride of Muay Thai" and Agaard smiles that his disciple is considering pride in this battle.
Once they start to overwhelm the weapons team Hyougo starts to have them work together more effectively. Just then, two masters: Chin Sougaku (crescent moon spade) and Ortal Sin (jamadhar) arrive and begin to put pressure on them. However, Ryuto, Renka, Koan Shokatsu and Genson Ryu, Renka's fellow disciples, also arrive and attack the enemy reinforcements. Once Ryuto tells them what to do, Kokin fights along side his YOMI disciples against Chin.
They all defeat the masters as after the armed forces retreat, they celebrate their victory.
In the Epilogue, Kokin continues his training alongside his master in Thailand.
- vs Alan Subishi and his disciples (won)
- vs karate members in school (won)
- vs Daimonji (won)
- vs Kenichi Shirahama round 1 (won)
- vs Kenichi Shirahama round 2 (lose)
- vs Marmaduke's Disciple (Ongoing)
- When Tirawit defeated Kenichi, his calculations about Kenichi's heart as a martial artist being dead are correct; the one thing he did not account for was Kenichi's masters using an unpredictable and otherwise very strange method of recovery by having Shigure maintain his fear. This is the only confirmed miscalculation he's ever made.
- Tirawit is the second YOMI member after Ryūto Asamiya to have ever defeated Kenichi. He is also the second person to have killed Kenichi, the first being Apachai Hopachai. Coincidentally, both of them are practitioners of Muay Thai and Muay Boran.
- Tirawit is the first and only character to have ever stood up after taking Kenichi's Korui Nuki and continue fighting. He is also the third Yomi member to take the Mubyoshi attack from Kenichi, his second most powerful attack.
- Tirawit was the only YOMI member Kenichi fought while wearing Saiga Furinji's Wrist guard, and Shigure's chain mail, both of which can withstand an attack from even a master class fighter (though they do not themselves dispel all damage from attacks).
- His "dreams for the future" are a refernce to "The Butterfly Dream"「莊周夢蝶」by Zhuangzi, a chinese philosophor focus on Taoism. The story itself is about Zhuang dreams of becoming a butterfly himself.
- History's Strongest Disciple Kenichi Official Guidebook, page 204. His ki-type is listed as "Dou" in his profile.