Shingo Komoi is a character in the Cardfight!! Vanguard Anime. He is a main character in Season 3, however he wasn't given very many dedicated episodes and was just there. He is also the only one of Aichi's "mates" that wasn't a main character in Legion Mate. He uses a Murakumo deck based around the Magatsu ride chain. He occasionally likes to try out different decks, as shown in Episode 114 when he uses a Narukami deck.
Shingo is first shown as seemingly a stalker to Kourin. Naoki notices this and threatens to beat him up for stalking Kourin, but then Shingo suggests they have a cardfight instead. It is later shown in the episode that his idol is actually Aichi, as Shingo became a fan of Q4 when he saw Aichi compete in the VF Circuit.
During the battle against Hitsue High, Shingo was placed against Miwa as he had never heard of him, prompting him to instantly judge Miwa as a weak opponent, only for Miwa to happily prove him wrong by demolishing him in a cardfight, Aichi later telling him that Miwa cardfights Kai on a regular basis.
Shingo then goes to the Cardfight Circle at the Middle School Division of Miyaji with Naoki to prove himself as a cardfighter so he will get popular with the Underclassmen and be better than Naoki. When they get there, they see the Cardfight Circle is run by Emi and Mai, also Rekka later on. Shingo gets in to a fight with Emi about how she speaks to Aichi although he does not know that Emi is Aichi's sister. He keeps on saying about how he is going to win, but then Emi actually wins the Cardfight.
He is shown to later on join the Cardfight!! Vanguard club since it was something he loved and Aichi was in it. He always had an interest in Cardfight!! Vanguard ever since it first appeared, but the academy was not too keen on it. Taking a chance to be in a club that he would enjoy, he joined the club after defeating Naoki.
In Volume 6, it is mentioned that he had a little brother who is currently in elementary school.