TV-Series
Description
Shinemon "Shin" Nitta became guardian to his niece Misaki Tokura after her parents died in a car accident roughly ten years before Aichi Sendou and Toshiki Kai's era. Still a Hitsue High School student then, he inherited both the family cat and Card Capital shop, destined for Misaki. During high school, Shinemon declared himself Card Capital's manager to thwart businesswoman Esuka Hibino's takeover attempts for her card shop chain. His impulsive methods included exploiting Esuka's feline phobia with catnip-lured cats. Despite his fierce determination to safeguard the shop for Misaki's future, he failed to reopen it initially, merely standing guard and unwittingly driving customers away—a flaw Esuka later highlighted.

As a young Vanguard fighter, Shinemon wielded a Genesis clan deck focused on accumulating five Force Gift Markers to open an Astral Plane and summon the formidable Grade 5 unit "Giant Deity of Distant World, Valkerion." Though initially reliant on this singular strategy, he later incorporated units like Astraios Dragon. He competed alongside friends Mark Whiting and Rive Shindou as Team Capital in tournaments such as the S Cup, battling Esuka for Card Capital's ownership. A pivotal defeat by Esuka temporarily cost him the shop, triggering depression before he rallied.

Rive Shindou mentored Shinemon in Vanguard, earning deep admiration. Shinemon, in turn, guided disciple Tatsuya Tachibana. He maintained close bonds with Mark and Mikuru Shindou (Rive's sister), with Mikuru and others like Nanami Gonomi hinting at unrequited romantic interest—oblvious to Shinemon.

Maturity transformed Shinemon into Card Capital's approachable manager (later overseeing both the original and Card Capital 2). He supported younger fighters strategically and morally, coaching Team Q4 in national tournaments and organizing training camps. His deck evolved to Murakumo. During the Link Joker crisis, he offered sanctuary to afflicted fighters. Revealing his past as Team Nippon’s member alongside Mark and Rive, he challenged Rive's son Chrono Shindou to a Murakumo deck match, pushing Chrono to confront his father's disappearance and decide Vanguard's role in his life.

Shinemon blends cheerfulness, empathy, and protectiveness. Passionate about teaching Vanguard, he invested in mentees' well-being, covering Team Q4's tournament expenses and using the game to help Misaki process trauma. His younger hot-blooded recklessness mellowed into wisdom, though he retained cunning, like withholding Chrono's family history to foster independence. Rive Shindou's interdimensional disappearance during a Cray incident devastated Shinemon, briefly extinguishing his fighting spirit and accelerating his evolution from brash teen to reflective adult.

Trivia notes: Age discrepancies arise (officially 38 at the original series' start despite high school attendance a decade prior); he alternates reflective daily glasses with rimless ones for cardfighting; and recurring name mispronunciations occur (e.g., "Lemon" or "Cinnamon").