MC Miya is a character in the Cardfight!! Vanguard anime series. He is a presenter that makes appearances at Vanguard tournaments. He tries to liven up the venue with good tempo dividers and witty talk.
(Source: Cardfight!! Vanguard Wiki)

A new generation of Cardfighting is about to begin. Chrono Shindou is your average middle schooler. His looks make people afraid of him, but he has a kind heart and is loved by children. One day Chrono opens his locker and finds a Cardfight deck no one has ever heard of: Gear Chronicle. Chrono takes it to the nearby Card Capital 2 where he meets one Kamui Katsuragi. Kamui teaches Chrono how to play the game and opens the way for Chrono to gain new friends and rivals solely by having fun, including soon to be teammates Shion Kiba and Tokoha Anjou. (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)

Team TRY3 members Chrono Shindou, Shion Kiba and Tokoha Anjou move forward to their respective high schools. Each member forms their own team in a bid to decide their own future. The three protagonists are set to clash as rivals in the upcoming large-scale tournament titled U20 Championship. (Source: Anime News Network)

Aichi Sendou and the Miyaji Cardfight Club aim the win the national championship, but problems arise after the timeline has been rewritten and taken Kourin off the team. Now Aichi and company must find a way to get back to 5 members to compete while the Student Council tries to shut them down. Meanwhile Kai battles his own demons as he tries to figure out how to reconnect with his cards, and Kouji Ibuki must decide whether he wants to give up the game or find a new way to play that doesn't involve deleting others. (Source: Anime News Network)