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Personality
Shikamaru's most distinctive character trait is that he finds all women bossy and "troublesome." Although the exception might be Kurenai who he visited in the hospital everyday and shows great concern for. The women he most finds troublesome are Temari , his mom and his teammate Ino. Given his mother's tyrannical personality, this isn't too surprising; however, his father shares the exact same attitude despite marrying her in the first place. Besides this attitude, he has expressed a notably mature interest in marriage and raising a family: "Marry someone who is not too ugly and not too pretty. Have two children, first a girl, then a boy. Retire after my daughter is married and my son becomes a successful ninja, and spend the rest of my life playing Shogi or Go. Then die before my wife.". Shikamaru dislikes fighting women, but ironically most of his opponents have been female until Shippuden in which they have all been male. It has been stated several times that his closest friend is Choji Akimichi, although he seems to have taken on the role of a close friend to Naruto as well since Sasuke left.
His favorite dish is mackerel and kelp; his least is boiled eggs. His favorite phrase is "What a Drag." His most desired opponent is no one since fighting is too troublesome. He changes his attitude significantly when he returns from the battle with Kakuzu. He is seen telling Kurenai that when he was young he thought of responsibility as troublesome, this being the reason he always messed up as a kid. He vows to protect Kurenai and her baby and to grow up so that he could become a "cool adult" like Asuma.
Abilities
Shikamaru is a very skilled ninja with an intellect in IQ of over 200 and, even back in his days as a Genin, is seen as one of the more perceptive characters in the series. In fact, he is so skilled, that even he fails to realize how he stands above most shinobi in the Hidden Leaf. Asuma noted that this is beyond genius and probably the smartest ninja in the Konohagure; Shikamaru also has a knack for being able to remember everything he witnesses in astonishing detail, which promptly suggests that he's got eidetic memory which enables him to better formulate plans and tactics. It can also be said that Shikamaru is very skillful at dodging attacks, as seen in his unfinished but nevertheless "won" battle against Temari. This is most prominently seen in Part I when he evades all three of Tayuya's Doki Demons. And in Part II when he evades the Akatsuki member Kakuzu and outmaneuvers his partner Hidan. Shikamaru and Kakashi evade Kakuzu's fire mask attack unharmed while his partners, Ino and Choji, barely tumble out of the way.
Shikamaru displays his talents only later in the second part of the Chunin exams. His primary supporting move is the Shadow Possession Technique. After the time skip that leads into Part II, Shikamaru also learns the Shadow Sewing Technique and many other shadow related jutsu as well as the ability to simultaneously use them in astonishing coordination, and even learning to use Asuma's Trench Knives and seemingly increases his intellect, now even being able to defeat a member of Akatsuki single-handedly, making him one of the few known to have done such a feat (alongside Sasuke and Naruto), as well as being able to analyze and discern the nature of their abilities after seeing it been performed only once using only the purest of logic. It might be noted that in each of his previous battles, Shikamaru makes use of strategy & planning instead of outright battle. Asuma has stated Shikamaru can think ten moves ahead and consider 200 possible moves in a second. But his real talent is always being able to choose the correct one. This enables him to defeat many ninja who according to him, "Cannot use their head." It is also notable that during the timeskip, Shikamaru has also developed in fighting skill, became visibly stronger that he was in Part 1, as seen when he was able to launch a surprise attack on Hidan which almost slashed the immortal's neck halfway through. In the anime, Shikamaru also diplayed the capacity to use summoning scrolls in conjunction with his shadow-based techniques; such as summoning an instant pool of water to conduct raiton attacks against an enemy.
Quotes
"What a drag."
"Sometimes I wish I was just a cloud..., floating along."
"Shadow possession jutsu!"
(About Kin) "And that's what I call using your head!"
To Kin) "Now who's hearing bells?"
(To Tayuya) "How many times do I have to tell you? The first move is always a feint."
(About Temari) "What an aggressive woman..., she's even scarier than my mom."
"How troublesome."
"Such a pain..."
(To Temari) "That is why women are..."
"I actually went out of my way to set the alarm last night, and I woke up before it went off. I don't even feel like getting up to turn it off. But I can't deal with this stupid ringing forever. Thinking about all of this is so troublesome!"
(To Hidan) "I only believe in the Will of Fire."
Trivia
Shikamaru is currently one of the three known shinobi, alongside Naruto and Sasuke, to have defeated members of Akatsuki unaided in a one-on-one fight, while Sakura had the help of Chiyo. The only difference is, that Naruto and Sasuke both had an advantage against their adversaries, either through sheer overwhelming strength or that the opponent was already worn-out when they fought them; Shikamaru on the other hand, had only his prodigious intellect to aid him against a literally immortal foe.
Shikamaru dislikes fighting women, but ironically most of his opponents have been female.
Source:
narutopedia