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He is a somewhat shy and timid young man who wishes to be a Vanguard Fighter, but has never had the chance to have a real fight until his second encounter with Kai. When starting to play Vanguard, he believes more in himself, becoming a powerful Vanguard Fighter. His Vanguard Circle's color is blue; but when using a Shadow Paladin deck, the color changes to dark blue.

According to Kerokero Ace September 2011, Aichi's surname is written with the kanji for vanguard (先導), the forward element in a military formation (and, of course, a reference to the title of the franchise). His forename primarily refers to the Aichi prefecture of Chubu, Japan. This follows a general trend in Vanguard of using historical names for characters. "Aichi" as a name originates from the third volume of the Man'yōshū, Japan's oldest collection of poetry, where it was referred to as Ayuchi, the Ayuchi-gata tidal flats. 

When he was younger, Aichi was a very shy and lonely boy who was frequently bullied at school. During the fateful encounter with Kai, who was still a friendly teenager, he gave him the card Blaster Blade , telling him to imagine himself big and strong, like the royal knight depicted on the card. Aichi couldn't picture himself any stronger at that moment, but the card gave him courage. He constructed a deck in the hopes of finding Kai and having a cardfight with him, but shortly after their encounter, Kai had apparently moved away. He eventually transferred to a different school after his mom got upset over the constant bullying.