Y/n pov
The next day as the birds were crying out in the distance, Kakashi was awake and laid out to recover his strength
Kakashi: ugh, I think I overdid it with the Sharingan
Y/n: you think
Naruto: hey sensei, your Sharingan is impressive, but if it puts that much strain on you, maybe it's not worth it
Kakashi: sorry
Tazuna: huh. Well, you did take down one of the most powerful ninja Assassins, so we'll be safe for a while.
Y/n: yeah, but what about the guy with the mask
Kakashi: he's from the elite tracking unit of the village hidden in the Mist. The most elite Shinobi only wear those masks.
Naruko: what do they do
Kakashi: the Anbu Black Ops, also known as The Inferno Squad, destroy all traces of a rogue ninjas corpse. The Shinobi's body contains many secrets ninjutsu, chakra, certain medicines used on his body. These are the secrets of his village. If his enemies find them, his people will be in grave danger. For instance, if I were to die at the hands of an enemy, he would try to analyze my Sharingan in the worst-case my entire Jutsu could be stolen and used against our home Village; it is a sacred duty of the Shinobi trackers to prevent this and keep the village Secret Safe if his ninja betrays his village. The Trackers hunt him down, eliminate him, and obliterate every trace of his existence. That's their specialty.
Y/n: what a nice job to have
Then he sat up and started holding his face like he was in deep thought
Naruko: hey sensei, are you okay
Kakashi: hmm? Oh yeah, to finish what I was saying, tracker ninja deal with the body immediately on the spot, so there's no room for error
Satsuki: is it that important
Kakashi: think about it. Do you remember what that tracker did to Zabuza's body?
Y/n: not really. His was gone with the wind and took the body with him
Kakashi: exactly. What why? He should have worked on Zabuza right there, as quickly as possible. Think of the weapons he used for the takedown. Do you remember what they were
Satsuki:...throwing needles. No way
Y/n: wait, now that you think about it, yeah, throwing needles doesn't seem like an instant kill method, huh
Tazuna: what are you all yammering about? You demolished that assassin
Kakashi: is the truth Zabuza's still alive
Naruko:&tazuna:!!!
Naruko: but we saw his body, and you said his heart stop
Y/n: his heart did stop, but it was only temporary to make it seem like the boy in The Mask killed him
Kakashi: the weapons that the tracker used are called senbon. Bacon Pierce deeply but rarely kill unless they hit a vital organ, not in the neck. They're modified needles used for medical treatment and acupuncture. Trackers are trained to know every detail of the human body; causing the heart to stop temporarily while keeping the body alive is an easy matter for them. First, he carries Zabuza's body away, even though it's much heavier than he is; second, he uses senbon, which have a precise effect but are rarely fatal with these two factors, we can conclude that the tracker wasn't trying to destroy Zabuza. He was trying to save him
Tazuna: come on, you're overthinking this, aren't you?
Kakashi: encountering suspicions, the ninja prepares quickly. Hesitation leads to disaster. Every Shinobi knows this saying
