Kakuzu concentrated on his rapidly beating heart as he forced his mind to focus to maintain the balance. The chakra inside his body was going haywire, while the newly acquired heart in his chest rapidly went through the changes. 

Kakuzu sat inside a room carved underground. The corners were covered with talismans to prevent his aura expanding outside, as well as prevent anyone from disturbing him while he dealt with the parasite that came along with the new heart. 

Orochimaru's cells that still lay dormant inside Kabuto's body had awoken after coming in contact with a new chakra signature. If Kakuzu was a weaker shinobi, those cells would just stay dormant while longer, waiting for a proper opportunity, a moment of weakness, to try and take over. But Kakuzu's body was far from ordinary. In fact, he could barely be considered as a human. And the cells sensed their peril that awaited them sooner rather than later, they desperate sprang into an action trying to wrestle control final act of the defiance.

Kakuzu maintained his focus even as his hearts begun to beat like a drum. His body felt like it was on fire, like every cell inside his body was burning up. Even though most of his body was devoid of such things, his hearts were a different matter. With each beat of his heart, the pain intensified and the invasive feeling that tried to take control of his body became more and more unbearable. 

It continued like this for hours. The war between the wills of the two shinobi was akin to tsunamis crashing against each other. Neither side had any thought of backing down, and clashes inside the body hadn't slowed down at all. In fact, Kakuzu felt that invasive cells were burning themselves up only to resist just a while longer as he slowly pushed the foreign will into the corner. 

He wrestled with the mental force that Orochimaru’s remnants produced as he begun to gradually overpower the invasive cells and purify the heart.

Then suddenly, it felt like an explosion went inside his body. It felt like even his soul wasn't left unscathed as the pulse of destruction spread from the small corner of his fifth heart. A deep sense of exhaustion washed over him, but it wasn't anything serious. He only laughed at the last desperate attempt at takeover and grinned in satisfaction when he sensed that waves inside his body calmed down. If his mind earlier felt like an ocean in the middle of the storm, now it was akin to a calm belt. There were no traces of invasive will inside the heart any longer. Something that had taken Kabuto months, had only taken him a day and a half. 

Kakuzu still took some time observing the heart in case anything cropped up. But when he made sure that there was no sign of danger, he let himself relax. 

It was only after a whole day had passed that Kakuzu woke up. He felt somewhat disoriented, and it took a moment before he regained clarity. It was not often he slept this long. Because of his strange constitution, he didn't require nearly as much sleep as others. Though, this time, the exhaustion was clearly not of the normal kind. 

He stood up and stretched his arms – a completely unnecessary action that was more of a habit from his earthly life. Though he couldn't really be considered the same person as before. The memories and experiences that he received from ruthless shinobi had morphed his personality into the colder one. He had long noticed those changes, and he sensed that they run deeper than it seemed. He wasn’t exactly delighted with it, even if the experiences helped him to quickly adapt to this world, with chakra and combat. Still, who would be content when their mind was meshed into someone else’s. At least he wasn’t forced into fight of wills with when he spawned into this world, he doubted it would end well for him.

Kakuzu shook off those thoughts. He could bathe in the existential dread shortly after. But first, he wanted to re-examine the stability of the fifth heart, as well as check how much his control over it had improved.

---

Lee and Guy were training madly like usual while Neji had been summoned by his clan for some reason. The village had been at peace for some time now. But Tenten knew that it wouldn't last long. 

She stood in the forest, holding a bow and gazing at the target several hundred meters ahead. Absentmindedly, she nicked the arrow as she fell into her thoughts. The future was grim. The war kept approaching the shinobi world yet there was not much she could do. When she first came here, she was stunned. First few days she thought it was a dream. It took some time to realize that it was reality. A new reality, and a new life that she had been given, without even asking if she wanted it or not. A new life, new opportunities. It didn't sound half bad. Yet, it was also filled with endless danger. 

She had many questions that remained unanswered. 

At first, she was reluctant to accept it. It felt like a new life was imposed on her. Who even was the real her? - she wondered sometimes. She did have memories of two distinct people, and one that she has been lacking was the one of a girl from Earth. But then, why did those memories feel dearer to her? She didn’t know. But despite her reluctance, as time passed, she couldn't help but enjoy the company of her teammates. Only small amount of time passed, het this peace had become something she wanted to protect. 

An arrow flew as it cut through the air. It curved in a strange manner before it found its target, lodging itself deep into the tree.

Truthfully, she was afraid. Her power felt awfully inadequate to deal with the challenges that awaited her, and everyone she cared for as well. She honestly could recall much, but what she did scared her. She hated to admit it but she felt like an ant, trying to challenge an elephant. What could someone like her even accomplish against the monsters that held power to shake the world?

Another arrow flew by, hitting the first on its end and landing on the same point.

She put more chakra into the third shot. The moment she released a string, the arrow blurred and next second it landed on the same spot, but this time it went through, leaving a deep hole inside the three.

Frustrated off her powerlessness she started going to a desolate place and vented of her anger at the innocent trees with a barrage of weapons. That was when she finally noticed that something felt off with her weapons. She knew that she possessed a talent for handling weaponry. But things weren't that simple. The memories she received told her that the accuracy, mastery and skill were far beyond what Tenten could previously accomplish. Not only that, but when she held a weapon, she could feel a surge of energy. It was barely noticeable with low-ranked weapons, but her strength definitely rose when she held them. And the strengthening further increase as the quality of the weapon improved. When she held a bow, her perception increased the most, when she held a dagger, her speed and agility, and when she held a bastard sword – her strength. She had to yet fully explore extent to her abilities, but it had given her some idea.

The discovery filled her with hope. Maybe she could change the future. She held no delusions of overpowering her way through the monsters, but no one said that she had to take on Akatsuki alone. There already were people for that, and the only thing she wanted was to keep people around her safe. If she was the reason for saving their lives, then maybe she wouldn't feel like this either.

So, her goal was set clear. She had to get hold of the stronger weapons. The weapons of the Seven Swordsman of Mist came into mind. The Kusanagi sword was a good option as well. And finally, the treasured tools of Sage of Six Path. If she managed to obtain them, she wondered how higher she could reach.