Kashitarou

Rintarou's son. He's the scientist type and big pervert. He is also the older brother of Rintarou's two daughters making him the eldest. Kashitarou spends all his time alone on Juuren moutain in Juuren village until Gama and Zenmaru joined him for a year as he trained them. He also seems quite perverted as he made lewd comments at Senka that later led to him being beaten to a pulp by her twice. In chapter 79, it was shown that he could do a double slash. His slash was so fast that Gama said it disappeared. He has a lot of knowledge when it comes to the body. Kashitarou was able to get past Gama using barely any movement and even got Gama in a vital spot. Kashitarou is a very skilled swordsman but appears to have no stamina. When traveling with Gama, Zenmaru, and Shin to Jouka, they were perfectly fine while he was out of breath. It is later revealed that he was born with a physical defect that reduced his strength and stamina. Despite his illness, however, he is still an extraordinarily formidable combatant, making up for his lack of physical ability with pure swordsmanship skill. It could be said that he has the most skill in martial arts in the entire series, as he is still able to defeat a member of Jinsuke's Personal Corps even with his infirmity. He is developing or has developed a sixth form. And may have taught it Gama and Zenmaru. He also calls Gama his ultimate creation. He is very confident, not only in himself but in Gama and Zenmaru as well because he spent time to train them.