The King of Underground Fights - S1.E36

Miwa spys on Kai who has begun fighting in underground fights in order to find stronger opponents. Underground Cardfights usually result in the loss of cards, and players do not abide by the rules that ensure fair play in a Cardfight. When Miwa discovers that Kai is searching for Jun, the King of Underground Fights, he goes looking for him. He confronts Jun, and is captured. Jun and Kai then have a Cardfight with Miwa and Kai's freedom at stake. Jun uses a Dark Irregulars deck against Kai, and puts up a fierce fight by making use of his cards' abilities. At the end, he attempts to use his ace, Edel Rose, and her critical strike ability to finish off Kai, but is prevented by the complete defense of Kai's Wyvern Guard, Barri. Kai and Miwa leave, with Miwa figuring out that he had been used by Kai to draw Jun out.