Isao Kachidoki

Isao Kachidoki is a character in the Yu-Gi-Oh! ARC-V anime. He is participant in the "Junior Youth" class of the Maiami Championship and is the Ace of the Ryozanpaku School.

Personality
In his Duels thus far, he has been shown as a very violent person, repeatedly physically assaulting his opponent during Action Duels to prevent them from getting cards in order to win at any cost.

Past
As a child, Isao was walking with Ryozan Godagawa, until he stopped and noticed a young Yūya Sakaki Dueling with his father, Yūshō Sakaki. His teacher told him not to think of Dueling as fun, as the path he was about to walk would be pitch black and full of darkness.

At one point in his life Isao had gotten second place in the previous Maiami Junior Youth Championship. According to Nico Smiley, Isao further evolved from the previous tournament by learning Fusion Summon.

Round 1
During his Duel with Yaiba Tōdō, Isao brutally beat up Yaiba in order to prevent him from getting any Action Cards, thus resulting in Yaiba's defeat in an One Turn Kill.

Round 2
During his Duel with Yūya, Isao once again tried to prevent his opponent from getting Action Cards through brutal force. While it seemed like Isao would win, Yūya entered Berserk Mode, which allowed him to Xyz Summon "Dark Rebellion Xyz Dragon" and beat Isao in an One Turn Kill. This Duel exposed Isao's ignorance towards Xyz Monsters as he thought that since they have Ranks, it was implied that their Levels would be 0 and he could activate the effect of "Idaten, the Star of Supreme Victory". When Yūya offered to help Isao up after the Duel, he disdainfully rejected it.