"How?" Haku watched, dumbfounded, as the kunai raced towards Zabuza's head, her mind trying to explain what she just saw. "Kawarimi no Jutsu (Replacement technique)? No, he was too far away and the shuriken was moving too fast."
Haku absently noted that Zabuza had chosen to release Kakashi rather than have a kunai buried in his forehead, though Zabuza did suffer a cut to his cheek as he dodged the kunai.
"How did he do it?" Haku mulled over the possibilities as she leapt to a tree closer to the shoreline, making sure she kept a close eye on Zabuza's fight with Kakashi; a fight Zabuza was losing. "He was too far to replace himself and as far as I know there is no bloodline that allows you to teleport."
Haku focused on the blonde boy who was treading water as both Jonin cast the Suiryūdan no Jutsu (Water Dragon Missile Technique), using their chakra to shape the lake water into towering, snakelike dragons which they launched at one another.
"Since the boy is treading water it's safe to assume that he doesn't know waterwalking, which rules out the chakra control needed for summoning." Haku narrowed her eyes, the answer was on the tip of her tongue, but it was absurd.
As absurd as Zabuza-sama, a former Kiri nin, struggling against Kakashi, a Konaha nin, in a duel of water-techniques. And yet, as the two dragons crashed and exploded into a shower of water-a sign that both men were equally skilled-there was only one answer.
"The only other technique that generates white smoke is when a person dispels a Henge no Jutsu (Transformation Technique). But to Henge yourself and allow your teammate to throw you at an enemy is simply…" Haku's eyes widened as she muttered, "Insane. This boy, a Genin, let his teammate throw him at Zabuza-sama!"
Haku looked upon the blonde boy in awe, and a slight amount of admiration. "He directly put himself in harm's way, all to save his Sensei." Haku was so lost in her thoughts that she was nearly swept up by the great deluge of water from Kakashi's Daibakufu no Jutsu (Great Waterfall Technique). Thankfully for herself, and Zabuza-sama, she was able to avoid the devastating technique.
She tree-hopped from the edge of the lake to where Zabuza-sama was blasted to. She arrived just in time to stop Kakashi from finishing Zabuza-sama with a kunai by throwing her senbon through Zabuza's neck and placing him in a near death state.
Kakashi checked the body on the ground for a pulse, and though Haku was confident that he would find none-it wasn't the first time she had had to "kill" Zabuza-sama in such a fashion-today had been a day full of surprises, so she decided to fill the dead-air and hopefully distract the Konoha Jonin from looking closer at the "corpse."
"Thank you for your help," she said in a monotone that helped her voice sound androgynous. "I hope you don't mind my interference, but I really wanted the honor of taking down one of Kiri's more infamous sons."
Kakashi looked up towards Haku with narrowed eyes. "Your mask…correct me if I'm wrong but that's an Oinin mask from Kirigakure, you were hunting Zabuza?"
Haku nodded. "Yes. Our corps had heard rumors that Zabuza had been operating around these parts, so I was sent to investigate and if given the opportunity; terminate." Haku absently noted that the female Genin shivered when she said "terminate."
Kakashi let out a "Hmm" in response. Though he looked relaxed, Haku could see that his body was still coiled like a spring, ready to strike at the slightest threat. "I thought Kiri was still in the midst of a civil war," Kakashi began casually, "Why would the Mizukage send out Oinin, especially one as talented as you appear to be, after a man like Zabuza?"
"Thank you for the compliment, Hatake Kakashi-san." Haku gave a minor bow. "It means much coming from a man of your stature. As for why Yondaime-sama sent me after Momochi Zabuza, I was sent for what he bears." Haku gestured towards Zabuza's blade that was strapped to his back.
"Ah, Kubikiribōchō," Kakashi said, sounding slightly sheepish. "That is a good reason to hunt down Zabuza. But what if Konoha wanted to take possession of the blade?" Kakashi asked with steel in his tone.
"Oh?" Haku's eyes narrowed into slits behind her mask. "How dare he think of taking Zabuza-sama's blade!" She was tempted to throw her senbon through Kakashi's damnable Sharingan, but a confrontation with Hatake Kakashi-even an exhausted one-would waste time. Precious time.
Time needed to remove the senbon from Zabuza-sama's neck before any permanent damage could occur. Thankfully, her reprieve came in the form of a waterlogged Genin wearing orange.
"What's going on here?!" The blonde shouted as he pointed an accusing finger at her. "Who are you?!"
"Relax, Naruto," Kakashi sighed as he stood up from next to Zabuza's body and walked over to the yelling blonde. "He's not an enemy."
"That's not what I asked—! I mean…what I mean is—he killed Zabuza…who wasn't a pushover…but he still got taken out by a guy who's only about my age! Like it was nothing! What, do we suck or something? What's up with that?" Naruto finished his rant. Haku could tell by his tone of voice that he was still hyped up on adrenaline.
"Maa, maa, Naruto," Kakashi ruffled his ragged, ruffian student's hair. "I can see how frustrating it can be to see someone as young as you who happens to be stronger than me."
Haku doesn't know why she said it, but she decided to offer the blonde some encouragement and compliment him on his efforts; "Do not be so down, Genin-san. I watched your battle with Zabuza and saw how your actions were instrumental in defeating him.
Not many shinobi would allow themselves to be thrown at a superior opponent, let alone volunteer to do so."