Yuto strongly resembles Yuya Sakaki; people often confuse him with Yuya, and the first time Zuzu Boyle saw him, she thought he was Yuya in a costume. Yuto and Yuya have nearly identical faces, except for their eye colors . His hair is close to a palette swap of Yuya's, black in the back with light purple in the front. Unlike Yuya, whose hair lies flat, Yuto's sweeps upward and to the right side of his head.
He wears a punk-style outfit, with a dull green formal shirt and dark blue tie, as well as a black cape-like garment with ripped sleeves and edges plus dark blue pants and black boot-like shoes. Save his cape, this outfit resembles the male Heartland Academy outfit, but is darker in color. Like Yuya, Yuto also wears a choker and wristbands, although his bands are a matching set—black with silver studs—and bear resemblance to those worn by Yugi Muto during Battle City. Yuto also shares Yuya's penchant for goggles, though his are of a sharper make and a more military style. He also sports a mask he uses to conceal his face, a red scarf tied around his upper right arm that is partially hidden by his sleeve, and can sometimes be seen with a larger red scarf around his neck. He abandons the goggles entirely after they are damaged in his Duel with Sylvio Sawatari, and later gets rid of his mask as well. During his time at the Spade Branch of Heartland Duel SchoolYuto wore tidier and more casual clothes; a black shirt under a black and cream-colored jacket, and a necklace.
Yuto and his dimensional counterparts' attire and hair are all based on the color of the cards that their dimensions are based on. As such, Yuto wears dark clothing to reflect the color of Xyz Monsters, while his hair is both black and purple, the latter color likely a reference to the color of DARK Xyz Monsters' Overlay Units.
Yuto and Yuya are similar in that both care about their friends and do not want to hurt anyone; this is shown by his reluctance to let Zuzu be involved in his fight. Through Lulu, Yuto developed the same views on Dueling as Yuya, namely that it should bring smiles to people's faces. However, Yuto is cold, serious, stoic, calm and collected, more so than any of his dimensional counterparts.
As a Duelist, Yuto is battle-hardened, telling Sylvio that he doesn't feel the sharpness of a sword nor the power of a bullet from his Dueling. He has a strong desire to not hurt anyone, thus he even shows mercy against enemies who are at a disadvantage, such as when he offered a recuperating Sora the chance to surrender during their match after holding back against him on purpose despite knowing that he belongs to Duel Academy. After regaining consciousness when Yuya was warped to the Xyz Dimension and realising what Duel Academy did to his homeland while he was away, however, he claimed Dueling to create smiles is an ideal that cannot be realised without destroying Duel Academy, taking over Yuya to brutally attack Aster Phoenix, albeit unsuccesfully.
Unlike his comrade Shay Obsidian, he is not reckless or impatient in his mission. Instead of simply attacking anyone he assumes to be an enemy, he would first interrogate them to get a clear idea of the situation, then leave them alone should they not be a real threat. He also tries to get as few people involved as possible. He was also quick to deduce that most of LID in the Standard Dimension is unaware of the war between Duel Academy and the Resistance.
Through Yuya's Berserk Mode, it is shown that deep inside his heart, Yuto harbors a deep vengeful hatred towards the Fusion Dimension and Duel Academy for the destruction of his hometown and for ruining his goal of making people smile with Dueling. While indirectly possessing Yuya, he doesn't care of the consequences resulting from his actions and only focuses on defeating his enemies. This is worsened when he was under the influence of the unknown darkness to the point he enjoys harming them.
Yuto's hometown, Heartland City, was once a peaceful city. Yuto attended theSpade Branch of Heartland Duel School, known for training professional Duelists. At one point he, Shay, and Lulu watched a Duel of Kite Tenjo, the ace of the Clover Branch.
Heartland was attacked without warning one day by Duel Academy from the Fusion Dimension. During the invasion he, Shay, and three other Duelists attempted to fight off the many "Ancient Gear Chaos Giants" that were Summoned, but their allies were defeated and sealed into cards, forcing Yuto and Shay to retreat.
At some point after the invasion, Shay managed to capture a Duel Academy Duelist, who Shay and Yuto interrogated for the reason of the invasion. He replied that he only did it out of orders. Shay tried to seal him into a card, but Yuto stopped him.
Sometime after the invasion, Yuto confronted Yugo, a Duelist from the Synchro Dimension riding a Duel Runner. He mistook Yugo's name for "Fusion" and assumed that the Turbo Duelist was working with Duel Academy, and Yugo brashly challenged him to a Duel, vowing that he wasn't losing until he'd beaten Yuto to a pulp. Yuto brought out "Dark Rebellion Xyz Dragon", while Yugo attempted to counter with "Clear Wing Synchro Dragon". Shay and several other Duelists arrived, and Yugo retreated.
After Shay informed Yuto that capturing the Professor's son may cause the Professor to panic and force him to release Lulu, he traveled to the Standard Dimension to oppose the Fusion Dimension, so Yuto followed his best friend there, too.
Upon arriving at the Standard Dimension, Yuto and Shay began their plan, however they went separate ways while still contacting each other on occasion. Upon finding out that LID is run by Leo Akaba's son, they assumed that it must be affiliated with Duel Academy. While Shay planned to attack LID personnel until Leo Akaba's son was forced to reveal himself, Yuto opted to Duel and interrogate LID personnel to find out about their connections with Duel Academy.
Yuto watched Leo Institute of Dueling from a distance, holding an LID badge. Later, he spotted Zuzu Boyle in front of a warehouse, about to confront Sylvio Sawatari, mistaking her in shock for Lulu. As Zuzu's Duel with Sylvio was about to begin, Yuto appeared and knocked out Kakimoto. He told Zuzu to stand back and took her place in the Duel. When Zuzu expressed annoyance at his interruption, he stopped her by telling her that he "didn't want to hurt her anymore."
Yuto started his Duel with Sylvio and Set all five of the cards in his hand. Sylvio mocked him, telling that he was disappointed that he didn't have any monsters. After Sylvio destroyed all of Yuto's Set cards with the effects of "Mobius the Frost Monarch" and "Mobius the Mega Monarch", he declared a direct attack, but Yuto activated three copies of "The Phantom Knights of Shadow Veil" from his Graveyard to protect himself. Sylvio ended his turn after destroying one of them and Setting a card face-down, and on the following turn, Yuto proceeded to Xyz Summon "Dark Rebellion Xyz Dragon". He used its effect twice to decrease the ATK of "Mobius" to 700 and increase his monster's to 4600. With one attack he brought Sylvio's Life Points to 100 and destroyed his monster, damaging the hangar in the process. He questioned Sylvio about the link between LID and "Duel Academy", but Sylvio claimed to know nothing about it. Concluding that LID indeed has no connection with Duel Academy thus isn't the enemy, Yuto tried to leave the Duel unfinished. However, Sylvio stopped him, saying the Duel was not over and activated his face-down "Ice Rage". He targeted "Dark Rebellion", aiming to inflict its boosted ATK as damage to Yuto, but Yuto activated "Phantom Spear" from his Graveyard, negating the Trap and inflicting enough damage to win the Duel. Using his powers again, Yuto rendered the "Phantom Spear" real, which pierced Sylvio's jacket and pinned him to the wall.
Before leaving, Yuto removed his mask. Zuzu, Sylvio, and his friends all mistook him for Yuya Sakaki, and Sylvio's friends fled, carrying their leader away. Zuzu, still thinking that Yuto was Yuya, asked him what he was doing dressed like that, when her bracelet started glowing. Once the light faded, she found herself alone in the hangar. As she wondered what just happened, Yuya (who had been alerted to the recent events by Ally) appeared and rushed to her. Zuzu asked him if he was really Yuya, wondering why Yuto looked so much like him.
Yuto stayed hidden throughout parts of Paradise City, eventually settling at the hangar where he committed his previous attack. He was spotted by Sora during his training with Zuzu, prompting Sora to chase and attack him. The two clashed with their Duel Disks. Yuto refused to identify himself, but when Sora claimed he wasn't from "here", he quickly replied "neither are you". The two were about to begin a Duel, but were interrupted by Julia, furious and determined to avenge her Professor. After an argument between Zuzu and Julia, Yuto vanished as Zuzu's bracelet glowed once more, and once again, Yuya came in running, concerned about her safety.
Yuto later witnessed Zuzu training with Sora once again, hidden behind a warehouse. Zuzu attempted to perform a Fusion Summon, which failed due to the fact that she forgot to put her Fusion Monster in her Extra Deck. Sora then said he noticed that Zuzu wasn't feeling herself because all she could think about was her first encounter with Yuto. Yuto recalled his Duel against Yugo, after which Shay asked him about Lulu. Zuzu's bracelet glowed once again, signalling the arrival of Yuya, and Yuto was teleported away from the area to a Duel between Herk and Shay.
When Shay interrupted a meeting between Julia, Zuzu, and Sora and was about to force Julia into a Duel, Yuto jumped in and pulled Shay's arm back. He removed his mask to warn Shay against his next actions and explain that they were wrong about LID being affiliated with Duel Academy, to which Shay retorted after pulling down his own scarf. When Shay noticed Zuzu, he mistook her for Lulu and began barraging her with questions, causing Yuto to punch him unconscious, then carry him bodily over the shoulder. When Yuto saw a "Polymerization" card in Zuzu's scattered Deck, he picked it up and remarked that it didn't suit Zuzu, prompting Sora to be offended. As Kit,Dipper, and Yuya came running over, Zuzu's bracelet teleported both Yuto and Shay away.
As Zuzu searched for Julia down an alleyway, Yuto appeared to stop her from moving further, as Shay was engaged in a Duel with Julia. Zuzu pleaded with Yuto to stop Shay, but upon receiving an unsatisfactory response, made to move past him. Yuto stopped her again, reiterating that he didn't want her to get hurt; Zuzu called him out for saying that, yet letting others get hurt, then asked him about his purpose. Yuto revealed that they were in search for Lulu, who had been captured and happens to look like Zuzu. He went on to say that Zuzu couldn't be Lulu, as Zuzu learned Fusion Summoning, the enemy's summon method. Zuzu retorted that she learned it to protect her comrades. Yuto then told her about he and his comrades' intention to build a world where no one can be hurt, and his hope that Zuzu survives if she gets involved in this battle, even if she has to use Fusion. Yuto told Zuzu his name before leaving.