Some basic info about the subject of this fanlisting, Uchiha Sasuke, the boy himself. Although there's nothing really in-depth, there are however UNMARKED SPOILERS FOR THE ENTIRE SERIES throughout this page. Go ahead at your own risk.
STATS (before time skip)
Name: Uchiha Sasuke
Height: 150.8 cm
Weight: 42.2 kg
Birthday: 23rd July
Blood type: AB
Uchiha Sasuke is one of Konoha Gakure's (Village of the Leaf) genins (low level ninjas). At the beginning of the series, he gets assigned to Team 7 after graduating from Ninja Academy top of his class. He's paired up with Uzumaki Naruto and Haruno Sakura, while the jounin (high level ninja) Hatake Kakashi is in charge of them.
Sasuke excels at both ninjutsu and taijutsu, and is able to perform quite a bunch of fire jutsus, such as Katon Ryuuka no Jutsu (Dragon Fire), Katon Housenka (Mythical Fire Flower) and Katon Goukakyuu no Jutsu (Powerful Fireball) -- all commonly used by members of the Uchiha family. Moreover, he has the ability of awakening the Sharingan (and he does, during a mission in the Water Country), an advanced bloodline which enables his eyes to copy techniques, among other things. Later on, Kakashi teaches him to master the Chidori, a powerful jutsu the jounin himself invented.
And so, you could say Sasuke is natural-born genius. The Uchiha Clan being one of the most famous and respected families in Konoha, everyone expected great things from the boy since the moment he was born. However, he had a high hurdle to overcome right from the beginning -- his older brother Itachi was amazingly talented and little Sasuke didn't even come near his brother's level at the same age. He began training hard every day, in order to reach his brother and be acknowledged by his father.
Unfortunately, tragedy hit the entire Uchiha Clan when Sasuke was still a little boy. All the members were completely wiped out one day (including his parents, Fugaku and Mikoto), without any warning or visible reason whatsoever. All except two, Sasuke -- who was the one to first find out about the massacre -- and Itachi... the one actually responsible for it. Itachi left his little brother live, fled Konoha and became a missing nin who ultimately joined the criminal organisation known as the Akatsuki.
Sasuke then find himself completely left alone very early in his life. Only one thing made him keep walking forward: the desire to kill his brother and avenge his Clan. And so he kept training in order to one day be able to beat Itachi, while at the same time isolating himself from everyone and everything that could distract him from his goal. Sasuke was already a silent and lonely child before the tragedy, but his loss seemed to destroy all capability of building human bonds.
And that's where Team 7 takes the stage. Much to Sasuke's discontent, Naruto, Sakura and Kakashi become his true family before he can even do anything to prevent it. The three begin knowing the real Sasuke and caring about him, while he in exchange would do anything to protect them. It's that, precisely, what makes him believe he's not improved one bit and is no closer to beating his brother than he was at the beginning. And so he makes the decision of cutting the bonds he took so much time building and take the people most important for him out of his life. He ultimately leaves Konoha and joins Orochimaru (another Konoha missing nin) in order to become stronger.
But of course, Sasuke is not a person you can easily forget about. Both Naruto and Sakura have made the decision to bring him back from darkness, whatever the cost may be, no matter how long it takes them. They're determined to save Sasuke from his own personal hell.