First appearance: Battle 6

Type: Dou/Sei

Type: Katsujin Ken

Martial Arts: Knowing him, probably everything (explained by his ability to copy all of the enemy's moves easily)

Hayato is Miu's grandfather and the undefeated elder of the Ryōzanpaku Dojo, who is said to have beaten 500 Shaolin masters to near death. He is also known as the "Invincible Super Man". His kicks have speeds that are still a blur even when viewing a replay of it at 1/1000 of the normal speed. If necessary, he is able to intimidate the other masters in order to maintain peace. Even using just 0.0002% of his power, he can easily overwhelm both Kenichi and Miu at the same time and rip a tree in half. He was able to defeat a master level opponent in D of D tournament with just one finger. Prior to building the dojo, he and his granddaughter had traveled around the world in his quest for peace. He has 108 special techniques so far and can copy any move an opponent uses against him, like Kenichi's "Saikyou (Strongest) Combo" and "Saikyou Combo 2," Soutenshu and Miu's "Hyōi Kazekirihane." He knows Seikūken and is the creator of "Ryūsui (flowing water) Seikūken" which Kenichi learned from him. However, his most used technique seems to be the "Human Shuriken."

One move that has been shown in the manga is "the Shockwave of Forgetfulness" a move which erases ones' memory. He seems to be able to decide how much is forgotten, as in the flash back to meeting Apachai the thug leader experienced total amnesia while Kenichi only lost his short term memory.

His training methods are the most frightening of all the masters at Ryōzanpaku, as bad omens like the splitting of tea bowls, pots and chopsticks were common at Ryōzanpaku while Kenichi was in the mountains training with him. Hayato is rather fond of Kenichi calling him "Ken-chan" and is the only master who apologizes to Kenichi for the hellish training that him and the other masters put him through. He later comments that Kenichi reminds him of himself when he was young. Though Hayato appears to have unmatchable power, Miu tells Kenichi that he had trouble fighting Silcardo Jenazard before. He and Kushinada know each other from the past.

Despite being the eldest and most powerful of the dojo, Hayato has proven to be rather irresponsible at times. He tends to recklessly spend the dojo's money on personal items and gets carried away whenever he has an opportunity to showcase his strength. Sometimes he's seen eating candy, especially lollipops. Also he mentions that he is getting weaker. After he used .0002% against Miu and Kenichi he told them that he needed a rest after using that much power. In Battle 231 he can use bi-vocal skill that can allows him to use two voices to speak. One time he used it for a duet at a karaoke bar apparently. Hayato can also use the left and right side of his body to perform separate actions and movements. In Battle 233 he is shown capable of reducing his voice to a degree where only one individual can hear his voice. With these abilities many, if not everyone, believe he is not human.