As a child, Shido was the ringleader and worst bully among those who tormented Naruto. Even then, he was tall and a strong fighter, repeatedly beating Naruto to a pulp.
Despite his irritation at Naruto's persistent defiance, Shido never held back. He also verbally intimidated and mocked the timid Hinata, though he never physically harmed her. Naruto often stepped in to defend Hinata, becoming the target of Shido's bullying instead.
Shido's parents had died before he could remember them. He spent his first five years in an orphanage before escaping to survive on his own.
He knew his parents had been killed by the Nine-Tailed Beast, but what truly irked him was the special treatment Naruto received while Shido struggled to survive. He looked down on Naruto for living off welfare while Shido had to fend for himself.
After graduating from the Academy, Shido was assigned to a three-man cell with his Genin classmates under the guidance of a Jonin.
During the Chunin Exams, their team failed the forest trial due to internal conflict and time constraints. Watching Naruto excel and garner attention during the exams filled Shido with humiliation.
Meanwhile, seeing Hinata get beaten to a pulp stirred a sadistic urge in him, making him think, "She deserves more!"
Following the chaos of the Chunin Exams, Shido continued to operate with his original team, but nothing significant happened. While Naruto grew through various incidents and missions, Shido's days passed uneventfully.
He laughed when he heard that Sasuke had defected from the village and Naruto had failed to bring him back. Later, when Naruto left to train with Jiraiya, Shido mocked him, saying, "Training's pointless anyway," but Naruto ignored him.
During Naruto's two-and-a-half-year training period, Shido idled away his time, half-heartedly completing simple missions.
Shortly before Naruto's return, Shido encountered Hinata trying to help an injured dog. He intervened, declaring, "It's beyond saving. We should put it out of its misery," and attempted to kill the dog, but Hinata stopped him.
"What's with that look? You're just a weakling like Hinata," Shido sneered, but Hinata stood her ground.
Frustration reaching its peak, Shido launched an attack.
He expected her to burst into tears like she used to, but Hinata fought back. Despite her lack of recent training, Shido's superior combat skills gave him the advantage. Still, he was surprised by how much stronger Hinata had become.
Gradually, Shido's blows began to land. With each punch and kick, he relived the excitement of the Chunin Exams, pouring more speed and power into his strikes. Hinata's pained grimaces and strained gasps only fueled his sadistic pleasure.
Even as she took hits, she muttered, "Naruto-kun is working so hard... That's why... I won't lose." The mention of Naruto's name sent Shido into a rage.
"Not Naruto again! Why is it always Naruto?!" he roared, winding up for a full-force punch. But before he could strike, Kurenai Yūhi, Hinata's Jonin instructor, intervened.
Asuma was also present, and they quickly subdued Shido. Fortunately, Hinata's injuries healed relatively quickly.
Due to his lack of remorse for the incident and his recent poor performance on missions, Shido was dismissed from his Genin status and sentenced to three months of confinement.
After his release, Shido abandoned his ninja career and took on ordinary jobs, but he constantly clashed with his coworkers and drifted from one job to another.
The money he earned vanished into alcohol and brothels, fueling a self-destructive lifestyle. Over time, his hair and beard grew unkempt, and his physique ballooned into a far heavier build than before.
One day, hearing that the Hidden Leaf Village had been devastated, Shido returned. There, he found Naruto being hailed as a hero for saving the village, basking in the gratitude of its people.
The sight filled Shido with unbearable irritation, but sensing the mood of the village, he realized it was best not to antagonize Naruto. "I'm sorry for bullying you before," he said. "You're amazing. I'm truly sorry."
But over two and a half years had passed since they last met. After graduating from the Academy, they had barely interacted, and Shido's appearance had been drastically altered by alcohol and his dissolute lifestyle.
"Sorry, who are you again?" Naruto replied, genuinely clueless. Though Naruto meant no harm, Shido felt as if he had been dismissed as utterly insignificant. Overwhelmed by humiliation and anger, he fled the scene.
Shido returned to his dissolute life in the entertainment district, drifting from one day labor job to another.
Then, one day, as the likelihood of another Great Ninja War loomed, his former Jonin supervisor summoned him back to active duty. Seeing this as a chance to start over, Shido promised to train diligently and lose weight, and agreed to return.
But he was far behind his peers, who had remained active as ninja all along, barely reaching the level of a Genin.
When the war began, Shido was assigned to a frontline unit—a position he knew meant certain death. During training, he deliberately sustained a severe injury to get himself reassigned to Konoha.
He continued to avoid combat under the guise of lingering injuries, using his medical leave pay for alcohol and brothels.
After the war ended, everyone returned to their lives. Shido remained a Genin, but his weight loss, natural good looks, and innate charm made him popular with women. He indulged in frequent dalliances, neglecting his training.
Years later, Shido learned that Naruto and Hinata had overcome a certain incident and begun dating, and he felt a surge of anger.
He was irritated by Naruto's seemingly smooth sailing (as Shido saw it) and by Hinata's growth into someone capable of romance.
At first, he had mocked them as a perfect match for two bullied kids, but soon regret and emptiness crept in.
Now, he couldn't bear to acknowledge the vast gap between Naruto, the hero who had saved the village, and himself, a worthless Genin.
That's it, Shido thought. I have a talent for charming women. I'll steal Hinata from Naruto... Someone as inexperienced in love as Hinata would be easy to win over. At the very least, I'll tear their happiness apart. I'll take her, then dump her immediately. I won't let them have a moment of peace... Shido vowed inwardly.
He approached the couple on their date. Naruto and Hinata recognized Shido, whose appearance had returned to normal.
They apologized once more. Shido had expected them to be wary, but the two, toughened by their experiences, seemed to have put the past behind them.
After that, he tried to approach Hinata, but she wouldn't listen at all.
Frustrated, he blurted out, "I know way more fun places and better restaurants than Naruto! He's nothing compared to me..."
The moment those words left his mouth, Hinata stopped her palm strike inches from my face. "Don't talk about 'Naruto-kun like that'!" she hissed. "It's because I'm with Naruto-kun that I have fun. I'll forgive what you've done to me, but I won't tolerate you mocking him!" Her glare was so intense, and the threat in her eyes so real, that fear rooted him to the spot.
He couldn't even bring himself to watch them leave.
Afterward, consumed by shame, he quit being a Genin again and returned to his old life. Every time he heard news of Naruto marrying Hinata or becoming Hokage, he would fly into a drunken rage, drowning his bitterness in alcohol and meaningless encounters with women.
One day, Shido met a suspicious man in a tavern who claimed to be from another world. The man knew everything about Shido, including his name and background.
He told Shido that he had been chosen as an existence to disrupt the balance of the world.
Shido's role was simply to act as he pleased, and the negative emotional energy generated from the resulting despair, anger, and sorrow would be vital to their organization.
The man instructed Shido to train in another world, acquire various powers, and then return to this world to indulge his desires without restraint.
Shido accepted the terms. He spent several years training in another world, mastering various powers, before returning.