Few years after leaving Konoha and following Orochimaru, Sasuke reviewed his aims : he wanted his vengeance, he wanted Itachi dead, and he wanted to restore his clan. And he couldn't wish for the latter while living under Orochimaru's shadow. That beast of a man was too thirsty for Uchiha blood to be anywhere around the family he'd build. As for his more primordial aim, he has no chance of tearing down Itachi if he couldn't get through Orochimaru.
After having his tutor dead, Sasuke had to choose what to do next; head for Itachi's head or rebuild the clan. The latter decision could need time, but the the first quick one may be fatal and take his life. Would the Uchiha have any future then ? Surely not.There would be nothing left to honour their memory; the man who reduced the clan to two persons in one night, killed his own parents, surely won't care about the future of this clan and even if he does, he doesn't deserve a family anymore.
When Team Hebi was formed, he chose a clever woman to join it. He may have forced boundaries, distance and standards with that woman who was lusting over him, but he did have another purpose, beside power, for wanting her in his team. She would carry his children, is how he thought.
Taking profit of his male teammates' absence, he asked Karine for a walk. That woman was so happy and didn't hide it.
They spent the whole afternoon together in that small village on the verge of a mountain. At dinner, while they were still alone together, Sasuke explained his behaviour. Karine was very astonished. She didn't expect anything romantic from him, she actually did expect, or wished, for something sexual, but the way he asked for this was too unexpected.
Karine's round eyes suddenly dropped sad. Her smile suddenly disappeared. Sasuke understood that he hurt her feelings, as if he asked her for being a tool he'd use, but he assured her that he'd never leave her if she becomes the mother of his children, that he'd take care of her and that she would have the same rights on them because he was entrusting her with the future of his clan if he dies on Itachi's hands.
Karine slowly rose her face, with a smile and some drops of tears in her eyes, clarifying that she was just too happy to hear that.
Three months passed since then, and there was no sign of pregnancy. Sasuke didn't enjoy the intimacy, felt weak and needy, and Karine somehow explained that they may need to do that few times per week. But after three months, Sasuke's patience exploded. He asked her what's wrong because she seemed to invite for the act way more too often, always claiming it will rise chances. It was absurd and he could tell she was playing with that. The Uchiha explained calmly that he needed a child, and that he would reward her however she wants later, but first things first.
Saddened at the accusation, of dishonesty, Karine isolated herself for a while. When she finally spoke again to Sasuke, she clarified that she wants playing any game. If he really wanted to know what's wrong, he should pass some medical tests. And that what he did urgently.
While in process, he questioned himself for a moment : what if he's sterile?
Sasuke's answers could wait; his rage got all of him when Itachi appeared to be in the neighborhood.
An aim reached. Itachi was dead by his side.
Reviewing all the pains he went by as he sat next to his brother's corpse, thinking of the future, Sasuke meditated on the word family and a worrying question rose again : what I'd he's sterile ? He gazed at his brother and thought that moment that if Itachi killed hundred of Uchiha, Sasuke doomed, perhaps, thousand more from the future and banished them from existence.
He shivered.
The revelations Tobi gave him, about Itachi's sacrifices, made him to insane. When he met his team again, Karine again, he knew she had an important and vital answer he was waiting for. Karine gave him what he was waiting for, but not the way he wanted it. He wanted news. Good ones, not bad ones.
"We can't have a kid because of sterility..." she started, but didn't finish.
Sasuke left.
The next time they met was to officially become members of the Akatsuki. Sasuke said that their band's name will become Taka. He gave a private talk with Karine for a very last time : "Let's never open the subject again. I don't ever want you to tell me anything related to that."
Gazing at the sea in front of him, realising the weight of all his loss and foolishness, regretting his brother's death more than anything, Sasuke's spilled painful tears.
With all the sadness, all the pain and grievances, Sasuke fell into the madness of destruction. He sank deeper into hate. He felt so hopeless and was ready to die at anytime, because he got nothing to lose and nothing to gain anymore, so he was so recklessly making his enemies pay their debts and taxes for peace. A peace that took away the last family he could have spared; his brother.
But there was light.
Buried so deep in that darkness, Sasuke still felt the warmth of love and want from Naruto, Sakura and Kakashi who were looking at him as one of them, beside all his crimes.
He lost his arm now, got back to reason, was forgiven for his crimes. He was accepted back in Konoha but still had to take a journey to rethink life. Find a reason to be.
The last person he talked to before taking that journey was Kakashi and Sakura. He promised Sakura to have more time with her next time. Thinking of that woman made him ashamed of himself; after so many years, after he almost killed her few times, after all the hatred he expressed and all his crimes she was still looking at him with so tender eyes full of love. He didn't deserve that love.
He thought that she wouldn't accept him nor still want him if she learned about his condition. But he knew that she truly loved him. Loved him enough to want to be his family and his home.
And that's when Sasuke thought about going back home.
The romance between Sasuke and Sakura started weirdly and developed quickly. So quickly he asked her to get married within few months of being a couple. Sakura still remembered what Sasuke expressed on their first Team 7 meeting : he wanted to kill someone and to rebuild his clan. He was devastated at the sight of the compound being razed yet he still didn't say anything at all, anymore, about rebuilding that clan. So Sakura was joking pretty often about having children, trying to push him to talk... in case he was shy ? But he wasn't. And it made him angry at some time, when perhaps he felt the need to be clearer with her because in case she wants children that bad, their relationship should end there and then because he is sterile.
Sakura was triply hurt by Sasuke's confessions : He was sterile and she felt hurt for him. He said that he already tried to rebuild his clan and that it wasn't like "he was waiting for her or she was the last woman on earth". And so, as if she wasn't that important at all, he didn't care about clarifying this matter from the whole beginning of their relationship, as if he took her for granted. Wasn't she ? Wasn't she stupid ?
Perhaps she was; few nice words and a sorry from him made her turn that page and move on and keep on loving him.
The periods weren't on time that month when Sakura felt weird. She didn't give herself a time to check her body; Sasuke was sterile after all.
When she finally did however, she found herself pregnant and there was a simply explanation for that : Sasuke was not sterile and those are super news that would brighten his life and lift a lot of burden off his shoulders.
Heading to tell him, she felt hesitancy when she met him, moody, and preferring to not go straight to the point and take a longer safer path, Sakura asked Sasuke on how he learned he was sterile. That Karine again. She didn't feel very jealous, because he clearly had no feelings for her, but she felt less important somehow.
When Sakura insisted on Sasuke to take another test and try to get a cure and all, Sasuke broke his calmness by humiliating her; he rose an old rivalry, between Orochimaru and Tsunade, and explained how Karine was the student of a better master and that she had better tools and knowledge for that. Tsunade was indeed a better medicinal doctor but Orochimaru was the biology doctor. In simpler words, Sasuke called Sakura dumber than Karine. In other words, he said that he trusted Karine more.
That's when Sakura felt unloved and betrayed.
Few months passed since that discussion, that argument, and Sakura seemed to be calmer. She never talked again about children or cure or anything. She was a happy wife-to-be loving fiancée and Sasuke couldn't ask for a better family seeing all he went through.
After a meeting at the Hokage's tower, Sasuke encountered a dangerous shade. After a long hunt and when he caught his target, for very confusing parameters, Sasuke was standing in front of a weird Sakura he didn't recognize. She was paler, sadder and didn't look like the woman he left in his house. His Sharingan attracted his ocular orbits lower; there was another chakra signature, of another human, inside Sakura... She was pregnant.
So the Sakura he lived with the few last months was but a clone while she, pregnant was somewhere else.
Infidelity. They parted ways there.
Ten years passed since then. Since Sasuke decided to live outside Konoha in an endless security mission. He was fleeing all that pain. He didn't want to listen to Sakura's explanations with all those fake tears while it was very clear how she got pregnant : infidelity.
She had no reason to hide that if she ever wanted to explain that it was his child.
Waiting for Naruto inside the Frontier's Castle, Sasuke should be meeting the Hokage for very important matters. There was a whole group of Uchiha Imposters going around with Sharingan lately and he could just feel disgust at the ugly idea. He was ready, with all his pain and controlled anger, to slay any fool who dared to hold the dear Sharingan eyes on his skull.
*steps*
Sasuke hid himself, just in case it wasn't Naruto who arrived. And yes, it wasn't. It was a child. The footsteps are a child's. Sasuke was sure it was that White Zetsu -like kid, but when he entered his vision's field he corrected himself : it isn't that child, but it is surely from the same group, this one was wearing a Haruno crest, so they're now imitating the Haruno too ? As if the Haruno had any power, ever. It was dangerous but he did got no time to wonder; he has to kill this enemy and get the place cleaned of any enemy before Naruto's arrival.
When he cornered the child, who turned over with a very scarred face, terrorised, he recognised something in those traits but couldn't tell.
It may have looked like...Itachi. But the face he saw now reminded him of that woman. That child said two word : "Are you..."
But Sasuke's hand was reaching for her throat, raging internally at the sight of Sharingan implanted in another body again. A very light question crossed his mind then : "But why does this Sharingan only have one tomoe ? Would an enemy come after me with only one tomoe ?"
Perhaps the third word that girl spoke answered his question and buried him under an instant avalanche of guilt :
"Dad ?"
