Taishi Miwa is a supporting character in Cardfight!! Vanguard: Asia Circuit Hen. He is a longtime friend of Toshiki Kai, having known him since childhood, and is often portrayed as Kai's only close companion. Miwa attends the same high school as Kai. Unlike Kai's reserved and intense demeanor, Miwa is outgoing, approachable, and enjoys joking around. He possesses a deep understanding of Kai and regularly plays cardfights with him, using a Kagero deck that mirrors Kai's own preferred clan. During the Asia Circuit storyline, Miwa temporarily takes charge of running the Card Capital card shop alongside Yuuta Izaki while the shop's owners, Shin Nitta and Misaki Tokura, are away competing in the Asian circuit. His primary role in the season is as a reliable supporter and grounding influence for Kai, offering friendship and stability behind the scenes. Though he does not take part in the main tournament battles, Miwa's loyalty and easygoing nature make him a steady presence within the group. His cardfighting abilities are demonstrated in later arcs, but in Asia Circuit Hen, he is depicted as a capable player who shares Kai's passion for the game.