He is the founder of the Vanguard Association. After his body died from forcefully summoning the Zodiac Time Beasts, he was "reborn" into a clone body.

His ultimate goal was to summon the 12 Zodiac Time Beasts in order to open the Stride Gate and create a world ruled by logic and reason, which would put an end to the countless atrocities born of humanity's irrational nature, at the cost of sacrificing Planet Cray. Due to his position and machinations he is the main antagonist of the series.

After judgement had been rendered on him, he was reborn into a baby by the power of the Zodiac Time Beasts as a chance to redeem himself and choose his own future.

He is one of the few original users of Gear Chronicle, and was the one who mass produced the clan for public sale.

Team TRY3: Chrono, Shion, and Tokoha, managed to win the championship of Generation Quest. In the mean time, however, Ryuzu Myōjin has a secret plan: summoning Zodiac Time Beasts of Gear Chronicle clan to Earth. Chrono and Kouji want to stop Ryuzu, but they are confronted by a mysterious group of cardfighters known as "Company" who share Ryuzu's ideology. (Source: Anime News Network)

[Profile (Haikyo)](https://haikyo.co.jp/profile/profile.php?ActorID=10587)

Diffriders referred to as “Apostles” from Planet Cray descend upon Earth. “Dragon Deity of Destruction, Gyze”, who destroys everything. The “Apostles” who envision the revival of Gyze, manipulate the power of the six “Zeroth Dragons” and invade the Earth. 

(Source: Anime News Network)

A major event known as "G Quest" is to be organized by the Federation of International Vanguard Associations (FIVA) this autumn. Those who conquer six Branch Quests will be honored the title "Generation Master" as well as the chance to become a Clan Leader. While members of TRY3 are all excited by new goals ahead, a massive conspiracy that would lead to the destruction of Vanguard has been secretly set in motion. 

(Source: Anime News Network)

This is the story of "Shinemon Nitta", the future manager of Card Capital.
 
10 years before the reunion of Aichi Sendou and Toshiki Kai, the card shop run by the Tokura family "Card Capital" was going out of business. Then came the attempt to take over the store by Esuka Hibino, the owner of a major card shop.
 
In order to protect Card Capital, Shinemon Nitta stands up as the "Self-proclaimed Manager!"
 
(Source: Cardfight!! Vanguard Wiki)

The history of -IF- world has been distorted and cardfights do not exist. Ibuki and Suiko get involved with Emi and Shuka.
 
A journey to regain the true history by four people begins—! (Source: Cardfight!! Vanguard Wiki)

Ryuzu Myoujin