Most ninjas in the Narutoverse are prideful, and because of this, they rarely consider retreating from battles where the chances of defeat and death are high. They prefer to fight and die for their village, rather than strategically withdraw.
Kaida might have done the same had he been originally from this world. But being a transmigrator, he understood the broader picture—living to fight another day is more important than dying for the illusion of peace in this world.
This perspective also influenced Yomi. After hearing Kaida's views on the world, she too became more practical, focusing on survival over blind devotion to the village. Now, they were training to master movement jutsu.
Every jutsu in the Naruto world can become deadly if mastered enough. Shisui Uchiha, for instance, was famous for his movement jutsu, earning him the title "Shisui the Teleporter" or "Shisui of the Body Flicker."
Shisui's mastery of the Body Flicker Jutsu was so advanced that he could create afterimages of himself. While some might argue that this can be replicated with the Clone Jutsu, they're wrong.
Clone Jutsu is basic and can easily be nullified if the enemy knows basic sensing techniques or can notice small details—something experienced ninjas excel at. Movement jutsu like the Body Flicker Jutsu, however, is different.
When used at high speeds, like Shisui's, it creates afterimages, making it nearly impossible for the enemy to predict the user's actual location. Sensor ninjas would struggle even more, as they'd sense the user in multiple places at once.
Because of this, Kaida and Yomi both decided to focus on mastering movement jutsu. Kaida, despite knowing the Wind Instantaneous Movement Jutsu, which was superior to Body Flicker Jutsu in terms of the distance covered, decided to learn Body Flicker as well.
Body Flicker is faster to execute and more practical in battle. Kaida also planned to ask Shisui to teach him how to master the technique, as it would significantly boost his power.
Kaida wasn't foolish—he knew his current strength was comparable to that of a Jonin, but he couldn't yet face an elite Jonin. Still, reaching Jonin-level strength before the age of nine was a sign of genius. If Kaida hadn't known about the future events, he might have been proud of this achievement.
However, knowing that even elite Jonin would be mere cannon fodder in the upcoming conflicts like the Pain Arc or the Fourth Great Ninja War, he strove harder. He now had people in this world he needed to protect, and to do so, he needed to reach at least S-Rank strength.
...
While they were practicing in the training ground, Shisui Uchiha received news that Kaida had returned from his mission. Pestered by his mother to check on Kaida, Shisui asked the guards for a favor, and being a respected ninja, they had no problem helping him.
Upon hearing that Kaida was back, Shisui immediately went to Kaida's house, only to find it locked. A thought crossed his mind: *'There's no way he's training right after a mission, right?'* But remembering his previous encounters with Kaida, he decided to check the training ground just in case.
...
When Shisui arrived at the training ground, he couldn't believe his suspicions were correct. Kaida and Yomi were indeed practicing movement jutsu. With his Mangekyo Sharingan and mastery of the Body Flicker Jutsu, Shisui easily recognized the techniques they were using.
*'They must have encountered something on the mission that motivated them to train this hard,'* Shisui thought. But being an experienced ninja, he decided not to ask about the mission. Instead, he used Body Flicker to appear directly in front of Kaida.
...
Kaida was practicing Body Flicker Jutsu as hard as he could, his Sharingan activated. He felt his Sharingan was on the verge of evolving, which is why he had only created three shadow clones—the training required a large amount of chakra.
Just as he was about to use the Body Flicker Jutsu again, he sensed someone was about to appear in front of him. Due to the constant vigilance required during their mission, Kaida had become sensitive to sudden movements.
Without time to prepare a jutsu, Kaida instinctively launched a chakra-enhanced punch toward the person about to appear.
However, the person teleported just before the punch connected, reappearing only a few steps back. Kaida immediately recognized him.
"Hello, brother! Long time no see," Shisui greeted with a smile.
But inside, Shisui was thinking, *'How is a kid his age this strong? That punch would have hurt even if I used Iron Skin Jutsu. And the speed... It's great that my brother is this powerful.'*
"You scared me there, brother!" Kaida said, laughing awkwardly.
"Hahahaha! Well, I didn't expect you to react like that. But let's leave that aside. Do you remember what you said the last time we met?" Shisui asked.
"Are you talking about visiting your house or the treat part?" Kaida asked.
"First, let's go to my house. Then we can talk about the treat," Shisui said, laughing.
"I'm sorry, brother, but I can't visit right now. Sensei said we might be called to the Hokage's office to submit our mission reports," Kaida apologized.
"No problem. But can you tell me when you'll visit? My mother is nagging me about meeting her nephew," Shisui asked.
"I can come in three days. I could come after we submit our reports, but I'm still under the effects of the soldier pill. I want to meet my aunt when I'm fully refreshed. But if it's urgent, I can visit after the reports," Kaida offered.
"Oh, no, three days is fine. I'll let Mom know. By the way, do you need my help with anything?" Shisui asked, hoping Kaida would ask for tips on mastering the Body Flicker Jutsu.
"No, brother. For now, I don't need anything. But I'll come to you if I do."
"Alright, but don't forget to rest properly. Resting is also part of training," Shisui reminded him.
"Yes, brother," Kaida replied.
With that, Shisui used the Body Flicker Jutsu to vanish from the training ground.
Normally, Kaida wouldn't trust anyone so easily. But Shisui was portrayed as a very nice character in Naruto, and since Shisui was his cousin (which Kaida confirmed from the family records in Konoha), he felt comfortable trusting him.
*(A.N.: YUP, I made this up, but come on—they must have something like that in Konoha, right?)*