TV-Series
Description
Taishi Miwa attends Hitsue High School. He stands as Toshiki Kai's closest childhood friend and confidant, frequently acting as Kai's sparring partner in cardfights and a bridge between Kai and others. Miwa exudes a carefree, sometimes comedic nature, contrasting Kai's reserve, yet holds deep concern for his friends. His typical attire is the Hitsue High uniform—blue jacket and pants with white trim—often layered over a pink hoodie. His Vanguard circle glows yellow.

Miwa ranks among Kai's only elementary school friends and the sole individual Kai maintained contact with after relocating. He actively sought to understand Kai's past, intervening during Kai's confrontations with underground fighters and even serving as collateral in an underground cardfight between Kai and Jun. Despite these efforts, Kai partially excluded him from his full history. During the Asia Circuit arc, Miwa managed Card Capital alongside Izaki.

Competitively, Miwa wielded a Kagero deck focused on units like Garnet Dragon, "Flash" (empowering other Kagero upon hit) and the Salamander series (retiring low-grade units). His strategy retired opponent rearguards while boosting his own units, often deploying Dragonic Overlord in the rearguard after empowering it with Flash. He uniquely retained older cards like Lizard Soldier, Undeux. Manga depictions showed him using a Nova Grappler deck centered on resting rearguards for benefits and multi-attack combos with units like Boomerang Thrower and Cat Butler, topped by Miss Splendor to bypass intercepts.

Later, Miwa confronted Kai after Kai's global travels, deducing Kai's link to the spread of Reverse. Challenging Kai with his Kagero deck featuring Dragonic Overlord the End, he lost to Chaos Breaker Dragon and was Reversed. As a Reversed fighter, he became Kai's subordinate, eliminating underground fighters and Jun to prevent interference. He subsequently fought Misaki using Dauntless Dominate Dragon "Яeverse" but lost to Omniscience Regalia, Minerva, reverting to normal and expressing remorse for Kai's isolation.

Following Aichi Sendou's disappearance, Miwa lost memories of him. During a cardfight with Kai at their school's Vanguard club, Kai activating Legion with Seeker, Thing Saver Dragon and Blaster Blade Seeker triggered Miwa's recollection of Aichi. Miwa later mentioned plans to attend an elite university with Misaki's academic assistance. He also encountered a butler linked to Aichi's circumstances.

In *Cardfight!! Vanguard G: GIRS Crisis*, Miwa reappeared as a Card Capital employee, humorously dubbed the Sub-Sub-Manager by Misaki. Within the "G Quest" narrative framework, he served as a guardian in the Dragon Empire.