A/N: Hey guys. I'd like to clarify one point. According to the canon timeline, Shisui died around 1-2 years before the Uchiha massacre. Itachi becomes an Anbu captain sometime after his death. However, I don't think the flashbacks in the manga ever stated the time between these events or even the fact that Itachi became an Anbu Captain after Shisui's death (correct me if I recall incorrectly). And I skipped the fillers in the anime after the fourth great ninja war started.
So I wasn't aware of the huge time gap between Shisui's death and the massacre and assumed that they happened in quick succession as they were shown in the manga. By the time I realized this, the story had long crossed the point when Shisui should have died (it should have been around the time Fujin graduated or when he was in the Genin squad). So, unfortunately, the timing of Shisui's death will not be consistent with the canon. The rest stays the same (with a few obvious changes I made).
Since it was getting late, most of the Uchiha clan members were in their homes with their families. For them, it was like any other evening. Their Jounins were aware that they would have to fight a tough war very soon. So they cherished their peaceful days with their family unaware of the tragedy about to befall them!
As soon as Itachi and Obito appeared in the clan, both immediately began the massacre. Obito freely moved through the walls and attacked the unsuspecting Uchihas. Itachi too flickered into their homes. Since he was the son of the clan leader, no one expected him to attack when he did. They began slaughtering the Uchihas with extreme ease and stealth.
While slaughtering, Itachi showed up in Uchiha Akihiko's house. Akihiko was having dinner with his wife and children when he suddenly got up and turned around to face the intruder. He squinted his eyes on seeing Itachi wondering what he was doing here. Most of the top-tier ninjas in the Uchiha clan were disappointed in Itachi and slightly suspicious of him. Unlike others who didn't expect any attack from the son of their leader, Akihiko was on guard and asked, "Why did you show up unannounced?"
Without replying, Itachi attacked him with his blade. Akihiko didn't have any weapons on him. He tried to move out of the way. Unfortunately, his body reacted a split second slower. That was sufficient time for Itachi's blade to slit his throat open.
Akihiko's family were shocked. However, before they could scream in horror, Itachi dealt with them too.
Some distance away from Akihiko's house, Obito entered Mieko's home. They too were having dinner. Both of Mieko's parents were at the Jounin rank. Sensing that someone had broken into their home, they both got up and prepared themselves. Mieko noticed her parents' actions and got alert as well.
She asked softly, "What happened, Mother?"
Her mother replied, "Someone has broken into our house. Stay on guard."
At the next moment, Obito appeared in front of them. Not identifying the masked intruder, Mieko's father made hand signs rapidly without caring about his house.
'Fire Release: Fireball jutsu!'
A massive fireball appeared in front of Obito who thought, 'Interesting. Their house had seals to alert them. Unfortunately, I can't let this fireball explode.'
He stood without moving and let the fireball reach him. However, instead of the fireball hitting him, the Uchiha family was surprised to see the fireball being sucked into his mask.
Taking advantage of the surprise, Obito went on the attack without giving them any time. Obito's speed was much higher than the three. Combined with their sluggish moments, they didn't last even a few seconds against him. Mieko saw in horror as both her parents were beheaded! Tears rolled down her eyes.
Her eyes began transforming as another tomoe appeared in her eyes. Obito watched her eyes and commented in a deep voice, "Interesting. To awaken 3 Tomoe Sharingans at your age. Very impressive."
However, Mieko was in no mood to hear any praise. She screamed, "Return my parents to me!"
She attacked Obito with all her might. However, a rod pierced through her heart in the next second. Mieko coughed out blood as her memories flashed in her eyes.
As she died, she heard Obito's deep voice, "Unfortunately, you don't have the time to grow."
As she fell down, she remembered the scene of Fujin saving her the last time. Unfortunately, she knew that it wasn't possible this time. It was already too late. She closed her eyes and fell to the ground.
Obito thought, 'A family with three pairs of 3 Tomoe Sharingans. How rare.'
In a flash, he took the Sharingans of all three of them and stored them before continuing his massacre.
Itachi and Obito continued massacring unopposed. After some time, Fujin opened his eyes in his basement. The honey badger clone that kept eye on the route from the Academy to the Uchiha clan saw Sasuke running towards home. Fujin's other shadow clones also received the memories. They prepared themselves to move after a few minutes.
Fujin left his basement and got out of his house. He analyzed, 'From what little I remember, there was some time gap between the massacre and the Anbu ninjas reaching the Uchiha clan compound. That is the only window I have.'
Fujin became a bit restless, but he didn't move away from his home. This entire mission was left to his clones.
In the Uchiha clan compound, Itachi finally entered his house ready to confront his father, only to see his parents not willing to fight.
Fugaku said, "I see, you have aligned with the other side."
Itachi controlled his emotions as he said, "Father, Mother, I"
However, Mikoto interrupted him, "We know already Itachi"
Fugaku said, "Itachi, just promise us this. Take Care of Sasuke."
With tears in his eyes, Itachi said, "I will."
Fugaku sensed Itachi's struggle and said, "Do not fear it. You chose this path, right? Compared to you, our pain will be over in an instant."
He continued, "Even if our Philosophies differ, I am still proud of you. You are a truly kind child."
With tears in his eyes, Itachi pierced his blade into his mother and father. Fugaku looked at his wife as he died. With his last breath, he said, "Destroy our eyes."
Itachi understood his father's wishes. Though he didn't fight against his son, he didn't want his eyes to end up in the hands of those who schemed against his clan and led them down this path of no return. Respecting his father's wishes, Itachi destroyed both their eyes.
With Fugaku and most of the Uchiha clan dead, the coup was finally averted. It was at this moment that Sasuke entered home with fear in his eyes. He saw his dead parents. After a small fight, Itachi placed Sasuke under Tsukuyomi and flickered behind Obito and said, "It is over."
Obito nodded and both disappeared. Fujin's clones stayed patiently for a few minutes. They didn't look at anything and instead focused chakra in their ears to pick up any sound. A few minutes after all sounds died down, they entered the Uchiha clan compound through the ground.
This was one of the main reasons why Fujin chose the honey badger disguise. They were known to be excellent diggers. On entering, all clones had a specific job.
One clone headed towards Akihiko's house while another headed towards Fugaku's house. One clone kept an eye on the entry route to warn others when the Anbu came. The last 2 searched the Uchiha clan compound to see if they could find Sora's house to see if he had the scroll.
The clone heading towards Fugaku's house reached there first. He focused chakra in his eyes and checked if there were any active chakras around him. Fortunately, there were none. He thought, 'Good. If Fugaku does have Mangekyou, then I want it.'
He got closer to his house while still staying underground but suddenly stopped as he felt danger. He focused chakra in his eyes once again as he wondered why he felt the danger. On noticing, he frowned, 'Shit, his house is covered in seals. And I can't identify many of them!'
He analyzed the seals and concluded, 'These seals shouldn't stop me from entering the house. But knowing what seals can do, I am afraid that there will be some consequences. It's fine if I am dispersed, but I don't want my main body to be implicated. That said, the rewards here are the greatest. Be it his Mangekyou or the fact that the Grand Priest's body is most likely to be with him.'
He decided to keep analyzing until he cracked the seals or the Anbu arrived.
Meanwhile, the clone that was heading to Akihiko's house didn't face any obstacles. Though Akihiko's house also had some seals, they were rather simple and Fujin's clone had no issues getting around them and entering the house.
After entering, the honey badger clone saw the dead bodies of Akihiko and his family. He immediately began searching for any and all scrolls in his house. He found multiple scrolls. Fortunately, one of the scrolls looked just like the scroll Sora had used to seal Zankoku. He immediately took it and checked it. He sighed in relief, 'This scroll still has his body!'
He put the scroll on his back. Fujin had inscribed a storage seal on the back of his clones before letting them go. After storing the scroll, the clone walked back to where he had seen Akihiko. He used his paw to open his eyes and saw that his eyes were still intact.
He thought, 'Good, his eyes are still intact. I saw that some of the Uchihas were missing their eyes. I guess that Obito took the eyes of the ones he killed while Itachi didn't.'
He summoned a container from the storage space on his back. He took both his eyes carefully and stored them in the container. He observed his eyes while analyzing, 'Though I have no intention of implanting a 3-Tomoe Sharingan in my eyes right now, it'll be good to have them. If I change my mind in the future or have any particular need, I can rely on these.'
Since he got what he wanted, he left the house. He went towards Fugaku's house to meet up with the clone outside his house. The clone noticed him approaching. He appeared behind the clone and tapped his back thrice. That was the code for saying that he had found the body of the Grand Priest.
The clone that was working on the seals around Fugaku's house looked back at his house unwillingly before leaving. They quickly dispersed to find the other clones and soon dispersed into 5 separate directions.
One clone headed towards the Akimichi territory, another towards Nara territory and one headed towards the Senju territory. They dispelled themselves after reaching close to their territories.
The last 2 clones moved towards the forests. One dispersed himself near the Konoha border wall while the last one moved towards Fujin's wind clones. On reaching the spot, he came out of the ground and handed them the storage scroll and the storage container. He went underground again and continued to move towards the border wall of Konoha and dispelled himself close to it. This way, all 5 clones were dispelled.
The Wind clones used Wind Instantaneous Body jutsu to reach another spot where Fujin's shadow clone was waiting for them. Fujin's shadow clone collected the items and returned home while the wind clones followed the same procedure as the Honey Badger clones.
Fujin saw his clone returning home. He accepted the items and returned back to his basement.