Naruto had a secret hobby. Reading

It would be very surprising to any who learned this fact, though at the same time it wouldn't be.

You see, Naruto didn't like to read non-fictional books, he liked to read adventure novels, crime stories, fantasy comics, he even read a few Icha Icha books every now and then.

This hobby eventually gave way to Naruto wanting to become a shinobi, to him, it was as if he was in one of his books living his own adventure.

After becoming a genin, Naruto fought tooth and nail to prove that he was ready for the bigger missions. Even if it was just a mission to wipe-out a bandit-camp, he wanted to do it.

The time finally came when Team 10, consisting of himself, Haruno Sakura, and Inuzuka Kiba (under Sarutobi Asuma), were given the necessary mission of losing their "innocence". In this case, making their first kill.

The camp was easily found, the plan laid out, and the three genin spread out accordingly while their sensei watched from above in the trees.

As Naruto stalked closer he began to play out a scenario in his mind that he created from all the stories he had read.

He made himself out to be some type of jungle predator. He and his three tribe-mates were out to kill the intruders of their land. He didn't notice how his facial features had changed to match his mental-image. A dangerous gleam in his eye, a predatory-smirk on his lips, and his canines elongated.

At the nearly-unheard signal, the blonde exploded from the bushes with a primal roar and easily struck down three bandits in quick succession.

Sakura had used a genjutsu that Asuma had taught her and was able to run unnoticed by the gathering bandits on the other side of the camp while throwing down explosive tags, she was clear of the blast range when the tags went off engulfing the bandits in less than a second.

Kiba and Akamaru had become a literal tornado that had surged through another part of the camp. Once a gray and white twisting funnel had turned blood red and brown before the Inuzuka and his partner came to a stop, still dripping with blood and looking a bit green.

Naruto had since called up a half dozen clones that assisted in ending the lives of the rest of the bandits.

When Asuma landed quietly amongst the human-debris, he simply smirked and with a nod of his head, he gestured for his students to follow which they did without a word.

The night was ours. The land purified with the blood of the interlopers. The woman at my side was a beauty to behold when she called upon the might of the flame to devour the uncouth fools. The man-beast to my left and his companion were one with the wind as they unleashed a gale of furious destruction on all those who dared to stand in nature's way. I...my hands had flowed through each intruder's neck and chest as easily as a fish moves through water.

Our leader looked upon us with pride and approval shining in his eyes. No words were spoken but they were as unneeded as his help this night. I walked tall, my head held high, allowing my hand to brush against the cherry-haired woman to my right every so often. She was obviously suited to be my mate but I would have to tread carefully, after all, "hell hath no fury"

While at first Naruto starts off just narrating his own little adventures in his mind as he goes about his missions, he doesn't realize that he is slowly starting to lose his grip on reailty.

As his stories began to change and as they begin to become darker, Naruto finds himself changing as well to suit his stories.

He begins to become deranged, delusional. He starts to view his "world" as reality. Whenever he feels as if someone is a threat to him in anyway, his mind drafts it to his "world" and twists it so that the person is a threat. A threat that needs to be taken care of.

The only three people that he trusts are his team.

Kiba is the first to fall into Naruto's world and decide not to return. Naruto, while out of his mind, is clearly stronger and more dominating than Kiba and so the Inuzuka reveres him as an Alpha. (no. not sexually)

Sakura falls later, though it's actually easier when she does, her "inner-Sakura" being the one to take over the body and since the inner-mentality had been trying to convince Sakura to become romantically-linked with her blonde teammate only to be rebuffed in favor of "Sasuke-kun", it wasn't long before the two became involved.