Bruno

Bruno is a mysterious young man from Satellite. He appears to possess similar skills to Yusei regarding mechanics and technology.

Story
Bruno washes up on the shore of a beach with amnesia. He is found by Mina Simington and Trudge; and they ask Yusei Fudo, Jack Atlas, and Crow Hogan to look after him. The three find out that Bruno's knowledge of mechanics is on par with Yusei's level, and he and Yusei begin to work together and develop a friendship. The two work two days straight on developing a new engine for the WRGP, becoming closer in the process.

Later, on the morning after they finished working, Yusei and Bruno are about to show Crow and Jack their new model blueprints on the computer, but discover they have been stolen. Jack blames Bruno for the theft because of his suspicion, but Crow points out that a thief wouldn't stick around after stealing something, erasing the blame an impulsive Jack placed on him. As the four try to think about the situation, Bruno realizes one of Jack's nearby cup ramen is missing. He then discovers a wrapper from one of them in the trash, assuming that the culprit ate one while extracting the data. As he examines the plastic, he realizes that someone couldn't have opened the seal with a glove on, therefore a fingerprint must have been left. Bruno finds a print upon further inspection, confirming his deductions and gaining some trust from Crow and Jack.

He and Yusei immediately begin to run the print through the Security database, but come across a firewall in the form of a Duel Puzzle, where the turn player must think through the current simulation of a duel and win that turn. Once they begin, the four are given 5 minutes until the mirrored servers are tracked and they are caught. Crow attempts first, but fails because of a set Mirror Force. Jack tries next, but fails to foresee the same trap and also loses. Yusei is expected to try next, but he insists that he may be able to figure it out. Yusei allows him to try, with only 2 minutes left. He then analyzes the situation and plays a combination of cards perfectly, completing the duel and overcoming the firewall, resulting in the Jack and Crow's complete trust.

The four discover that Lazar was the thief of the engine blueprints data, causing the four to go after him. They follow the limo he is seen getting in. While riding, Lazar sees the the four chasing him and decides to try to lose them.

The chase leads to a foot chase in a mall, while the four are trying to hide their appearance from Lazar. However, he is fully aware of their presence and allows Crow and Jack to catch him. He escapes and provokes them to chase him, splitting up from Bruno and Yusei. Lazar leaves hologram decoys around to lead the two groups on wild goose chases while he leaves the area in the all the commotion to catch a cab. He realizes that they are chasing images and dismantles the decoy he and Yusei were following.

Bruno and Yusei then follow Lazar on their Duel Runner to the the headquarters of the Infinity Trio. While wandering inside, Placido is alerted of their intrusion and locks down the inner halls, splitting Yusei and Bruno. He decides to find Crow and Jack and bring them there to help Yusei.

While looking for an exit, He finds a locked door. With his mechanical expertise, he unlocks it, only to be found by Placido. Upon seeing him, Bruno suffers a massive headache, possibly because he recognizes the attacker from his past memory. Placido takes advantage of this and knocks him out.

He is later waken by on the floor of the room he discovered, a large storage facility that was used for recently activated Riding Roids. He hears the self-destruct alarm set off by Placido. He is found soon after by Crow and Jack, who are looking for Yusei. Jack notices a room above and assumes it is the control room. The three immediately run up a flight of stairs leading to the room, where he attempts to disarm the self-destruct sequence. The controls are unresponsive, but a security camera view of Yusei appears. Jack finds the microphone and they warn Yusei of the situation. Yusei tells them he has a plan and to go on ahead. Crow and Jack are hesitant, but do as Yusei says. Bruno protests, not wanting to leave Yusei behind. Jack punches him in the face, threatening to drag him out of there if he won't go willingly. Crow remarks that it's not easy for them either.

As they leave down the hallway that Crow and Jack first came through, Jack explains that Bruno doesn't know Yusei like they do. He and Crow tell him that Yusei wants them not to worry about him, and that he'll believe in even the smallest chance of winning. Bruno accepts Yusei's reasons.

The building explodes just as the three make it out far enough to be safe. They wonder if Yusei is alright and then see Lazar floating out of the smoke hanging onto his balloon, holding Yusei in his other hand. He states that Jack was right. After Yusei lands, the three run to greet him.

Sometime later, he is at the the Kaiba Dome duel track with Yusei, Jack and Crow as they practice tag dueling for the WRGP. After Jack leaves the team, a week passes and Sector Security puts out a warrant for his arrest. Bruno, Yusei and Crow head to the Security headquarters and learn of a turbo duelist that seems to be Jack causing others to crash during the game. Crow outbursts at Jack's denial and indifference to the matter, causing Jack to become even more apathetic to the situation and his friends.

Later, at their apartment, he scolds Crow for having said those things. Crow admits his regret at doing so, now that Jack won't talk about what may have happened. He says that Jack could very well be guilty. Leo suggests that they should find the real culprit to prove Jack innocent, but without any clues, Yusei says it's best to leave the case in the Security's hands.

After the imposter Jack was revealed and defeated, life seemed to return to normal. Yusei, Crow, and Jack all continued to work on their Duel Runner with Bruno's help.