My fav Naruo character is kabuto.
Kabuto considers himself a simple man with simple goals -- he is only a follower of Orochimaru, and he only wants to do his bidding. Managing that is enough to make him satisfied.
His age had not yet reached the double digits when he was first taken to the island, as the assistant of a member of the AKATSUKI Initiative. His studies were considered unorthodox--even at his young age he had no guilt in knocking someone out and testing on them with substances he was not sure of. If someone was to die, he never so much as batted an eyelash at it (instead, he'd dissected the body and study that, too).
It's not as if Kabuto remembers why he was this way, though, as he's got no knowledge of his life prior to the initiate. He never questioned it; it didn't really matter.
He was young, but a genius, and someone else set his sights on him for that. Orochimaru approached him and asked if he'd like to escape life in the initiative, if he'd like to be his right hand man in making a new group of people. He only took the opportunity because he could, and not for any other reason -- he is like that, often, and for that reason he calls himself simple.
Kabuto was sent out to find people (young, yet smart and capable like him) to come and join them on the island. He immediately went to the orphanages where no one would miss them, and plucked out quite a number of people. It was not kidnapping--he simply told them where to go, and how to stage it to look like a kidnapping so he would not get caught. If they did it successfully, three days after they were told to be gone in the newspaper, he would meet them there and have them sent off to the island.
There were others that were not orphans, or did not need to look like they were kidnapped, but they were harder for him to get or find out about. It was after he'd been questioned for the kidnappings, and had escaped the cops--his name and face were everywhere (he even kept a clipping from the newspaper about him that he'd torn out), and he had to be certain they would be people that he could buy over from the very beginning. Sai was one of those, hopeless, and at his wits end. He made a promise of anything Sai could ever want, and that he could even go home after just three years of answering to Orochimaru, and the choice was made without hesitation. Kabuto lied to many people like Sai, and every one of them fell into it.
He wasn't sure why he told Sai that he only had to spend three years there, just as he wasn't fully sure why he said most of the things he did. Kabuto did, however, wonder what the outcome of his words would be--how they would affect people, like it was just another study of his. He said some things only to know that the words were thrown out there, just because he could. It was a simple reason, and there wasn't much more to it than that. Kabuto liked to believe so, anyway.
By age twenty four, he had convinced at least fifty people to join them in their new home, not having once been unsuccessful in getting them to make up their mind in coming or no. Kabuto never failed Orochimaru, after all.
One day, he made the trip back to the island, a place he considers his home because he doesn't remember life before it, and returns to Orochimaru's side. He does not mention that he's been keeping in touch with the initiative, just as Orochimaru doesn't say that he suspects it. Things are kept simple that way.
Now home, Kabuto continues with his studies of the island, and of its people, and will disappear for days and say that he got lost (because he misplaced his glasses, even though he doesn't need them, but no one knows that-- "a real magician lives the act," he vaguely remembers from a movie he saw when he was away from the island) or that there was a threat. He knows the island just as well as anyone that had been in the initiative should, and so Orochimaru knows the truth, but never says an ill word to or about him. Kabuto does everything he asks, after all.
On a quiet day, Kabuto leans back and looks at the sky and says to Orochimaru, "I suspect I was hypnotized when I first came here," to explain his loyalty and oddness as a child. He goes on to say, "I think it broke when you and I left," to explain that there is no more loyalty to the initiative. He is not sure of the truth of his words, but he thinks that it sounds plausible enough, and at least it was something for Orochimaru to think over.
Kabuto's life is full of secrets and lies, but the fact that he never lets them be known to the public is what makes him seem like a very simple man.