The days passed with suffocating tension. Saruto's suspicion about Kai lingered, especially after his son's bold claim regarding the Second Hokage's death. Though he wanted to dismiss it as a desperate excuse, Saruto couldn't forget Kai's intense conviction.
Meanwhile, at the Hokage's Summit
Tobirama Senju led negotiations with the Land of Thunder. The discussions were tense but critical for maintaining fragile peace. Yet, outside the summit, the deadly Kinkaku Force lay in wait, prepared to assassinate the Hokage and disrupt Konoha's stability.
The ambush came suddenly. Tobirama, realizing their dire situation, chose to sacrifice himself to save his comrades, naming Hiruzen Sarutobi as the Third Hokage before charging into battle alone.
News Reaches Konoha
The following morning, Saruto returned home visibly shaken. Kai watched as his father removed his armor with trembling hands.
"What's wrong, Father?" Kai asked, his voice cautious.
Saruto looked at him, his face pale. "The Second Hokage… is dead."
Kai remained silent, waiting for more.
Saruto continued, "During the negotiations, the Kinkaku Force ambushed him. Tobirama sacrificed himself to protect his team and named Hiruzen Sarutobi as the next Hokage before he… fell."
Kai lowered his gaze, feigning shock and sadness, though inside, relief washed over him. "I told you, Father. I told you this would happen."
Saruto stared at him, his voice sharp. "How? How could you possibly have known this? Is it truly because of your ability?"
Kai nodded slowly, choosing his words carefully. "Yes. My Sharingan has shown me glimpses of other worlds—parallel versions of ours. In those worlds, I saw the same fate play out for the Second Hokage. That's how I knew. And there's more I've learned from these visions, things that could help us."
Saruto's skepticism wavered, curiosity taking hold. "What kind of things?"
Kai hesitated, as though weighing whether to reveal more. "Techniques. Jutsu that don't exist in this world yet… but could."
Saruto's brows furrowed. "Are you saying you've learned jutsu from these visions?"
Kai nodded. "There's one I can teach you. It's called the Rasengan. It was developed by a Hokage in one of the worlds I saw."
Saruto crossed his arms, his doubt returning. "A Hokage's technique? And you've learned it?"
Kai smirked faintly, standing. "Not just learned it—I can perform it."
He held out his hand, focusing his chakra. A small, swirling sphere of raw energy began forming in his palm, its power radiating through the room. Saruto's eyes widened in shock.
"This is the Rasengan," Kai said, letting the technique dissipate. "It's an incredibly versatile and powerful jutsu, and it doesn't require hand seals. I can teach you how to create it."
Saruto stared at his son, his disbelief slowly giving way to awe. "You… actually created that. Show me again."
Kai repeated the process, forming the Rasengan more quickly this time. He explained the technique step by step: chakra control, compression, and rotation. Saruto listened intently, his skepticism giving way to intrigue.
"Why would you share this with me?" Saruto asked after a long pause.
"Because I trust you, Father," Kai said, his tone sincere. "And because I believe this technique could protect our family and our clan. But you can't tell anyone where it came from—not the clan elders, not the Hokage. No one."
Saruto's eyes darkened. "If what you're saying about these other worlds is true, then secrecy is the only way to protect ourselves. I'll keep this between us."
Kai nodded, relief washing over him. "Thank you, Father."
As Saruto began practicing the Rasengan under Kai's guidance, the tension between them eased slightly. But Kai knew this was only the beginning. He had revealed just enough to earn his father's trust, but the secrets he carried were far deeper—and far more dangerous.
This chapter incorporates the Rasengan, tying it into the parallel-world narrative while deepening the bond and tension between Kai and Saruto. Let me know if you'd like to tweak or expand any part!