The passing of time did not make battlefields less unforgiving. The moment that Kaguya, the Rabbit Goddess and mother to the world of ninja, picked the divine fruit from the God Tree and consumed it she erased the canvas of history, starting a painting anew; whether due to fate or simple misfortune, the fresh canvas was very quickly stained red with the blood of the men, women, and children who could not escape the clutches of endlessly waging war, and the cycle of hatred and sorrow continued into the new age.
Kakashi Hatake knew of the effects of war firsthand. As a child, pride had blinded him to the true weight of the baggage that shinobi were required to carry, and he attempted to take the load upon himself; it was not until he was able to see through the eye of a friend that he realized that the key to success and fulfillment in life was creating and strengthening the bonds a person had with his or her friends. Unfortunately, this enlightenment came about too late, and he lost many of the people he cared for before the chance to illustrate his resolve presented itself.
Death and destruction did not wait for Kakashi to reach adulthood before rearing their ugly heads, so alternatively, he matured rapidly in order to stand tall against the harshness of the world. His mother's light extinguished before he was even old enough to form lasting memories of her, leaving his father, Sakumo Hatake, to raise him. In his early years of life, Kakashi admired his father for his strength, wisdom, and reputation; however, his feelings for Sakumo faded into resentment and shame the day that the man he looked up to most took his own life.
It was expected that a shinobi put his or her mission above all else, but the White Fang of the Leaf could not bring himself to sacrifice the lives of his comrades for the sole purpose of continuing a possibly fruitless assignment. In a moment of chaos, he chose to abandon his mission to spare his teammates from death; unfortunately, his decision left him vilified by the Land of Fire, even by the very people that he saved.
First, Kakashi observed as the almost unrivaled skills that his father possessed waned into fragility; next, he witnessed him fall prey to the temptations of depression, and lastly, he stumbled upon what remained of the man that he had once idolized—just a lifeless body lying limp on the cold floor of a darkened room. In place of sorrowful tears, his fists clenched and his teeth gritted at the disgrace of suicide. He grew immediately bitter for being abandoned and resentful toward the end that his father opted to meet instead of facing the consequences of his actions.
By allowing others to live, Sakumo had resigned himself to an early, self-imposed demise.
"Following the Shinobi Rules must always take priority, no matter the situation." Due to the fate that the White Fang of the Leaf suffered, this motto completely dictated the way in which Kakashi lived his life. He passionately believed that those who broke the rules were nothing more than scum and that the world reserved no place for trash of that kind; the pride that manifested within him thanks to his ideologies left him lacking in teamwork ability despite how he excelled in every other field, putting him at odds with the team that he would be paired up with upon achieving the title of Genin.
Obito Uchiha, Rin Nohara, and sensei Minato Namikaze—these were the names of the individuals assigned to be in a four-man squad alongside Kakashi. While Minato and Rin possessed the maturity to handle his strict attitude, he and Obito were constantly clashing over one thing or another. He was a prodigy, becoming a jonin—a high ranking ninja—before he even officially entered his teenage years; Obito, on the other hand, was a slow-paced learner who oftentimes cowered in the face of danger. The differences between the two young ninja were stark, but although Kakashi was undoubtedly the stronger and smarter of them, it was still he who had the most growing up to do.
It was with Team Minato that the young prodigy was exposed to the horrors of war. During the Third Great Ninja War, he and the rest of his squad were assigned to destroy Kannabi Bridge in the Village Hidden in the Grass in order to cut off the supply line being used by shinobi from the Land of Earth. Being needed on the front lines, Minato entrusted leadership of the team to Kakashi as he was qualified for the position thanks to his status as a jonin. Obito vehemently objected to the arrangement, but in the end, the students and their master parted ways.
Tragedy struck before the members of Team Minato were able to accomplish their mission; Rin, who specialized in medical ninjutsu and held a unique place in the cowardly Uchiha's heart, was captured by the enemy, and Kakashi was confronted with the same dilemma that Sakumo faced years prior: should he attempt to save his comrade or continue to prioritize the mission? Though he refused to allow his inner conflict to show through his self-righteous façade, the child within him screamed out for the father that he thought he had come to detest; remembering the lifeless body of the parent he once revered and all of the whispers that led up to that point calmed his raging thoughts and brought him to the conclusion that destroying Kannabi Bridge should take precedence over saving their comrade. He would be damned if he suffered the same fate as his fool of a father.
"The two of us need to carry out the mission by ourselves," the young prodigy stated, avoiding the pleading eyes of his remaining teammate.
"W-What?! Do you know what you're saying?!" Obito angrily retorted.
"Yes."
"But…Rin! What about Rin?!"
"We'll think about Rin later," Kakashi remarked. His pride did not allow him to tell Obito the truth; he could not reveal to him that he made the choice almost solely on the experience that he watched his father suffer through, so instead, he attempted to reason with his ally. "They want to know what our plan is, so they won't kill her straight away." Despite the confidence that flowed off of his tongue with his words, he recognized that there was no way to guarantee their friend's safety. He was doing nothing more than betting on the enemy wishing to extract information from her before disposing of her. Seeing that Obito still appeared unconvinced, he continued. "We should be more worried about them learning our tactics. To a ninja, his mission is everything; that's the ninja code."
Just as they had time and time again, the two boys argued from very different viewpoints, precious time ticking away as their voices got progressively louder. Kakashi believed Obito to be immature and spineless, so when the aggravated Uchiha made an attempt to end the conversation by saying, "You and I just don't get along. There's no point discussing it anymore," he was taken aback momentarily.
The young prodigy could see that his teammate had made up his mind—he was going to aid Rin in any way he could. Deep down, Obito's willingness to abandon the task at hand to rescue a comrade frightened Kakashi, and out of this fear, he said the only thing that he could think to in one last ditch effort to keep the cycle of scum from repeating itself. "You don't get it…You don't know what happens to people who break the code."
"I believe the White Fang was a true hero," Obito stated abruptly, turning his back to Kakashi and causing him to falter. He was not aware of it, but the words that he spoke next would become the new motto that the young prodigy lived his life by: "Sure, maybe in the ninja world, those who break the rules are scum…but you know what? Those who abandon their comrades are even worse!"
After finishing his speech, the determined Uchiha darted off into the depths of the forest, leaving Kakashi to his own musings. "A true…hero?" he thought to himself, still shocked regarding his teammate's sudden change in behavior; all of a sudden, an image of his father's smiling face—a smile that depression and isolation had taken from him in his final days—flashed in his mind. "Dad…Why did you do it? Why did you choose the lives of your comrades over completing your mission? You died a piece of trash, but…according to that idiot, I'm even worse for planning to leave Rin behind. Even at the cost of your sanity, was saving your friends worth it…?"
Kakashi glanced in the direction that he knew Kannabi Bridge was in and then in the direction that Obito had gone. For so long, he had justified the way he lived his life by looking down upon Sakumo's actions, but the fact of the matter was that he was not his father; whether he saw fit to proceed with his duties as a shinobi or to help save Rin was his decision alone. Thinking again of the man he once idolized, he made his choice. "I suppose if even one person remembers you as a hero, your death was not completely in vain…Now, thanks to Obito, two people will recall you for the hero that you were, and just like you, I refuse to be less than scum!"