As the explosion caused by the Explosive Tag set beforehand divided Yagura and Mangetsu from the ANBU, Zabuza used the Hisenken (Flying Revolving Sword) and throws Kubikiribōchō at the Yagura and Mangetsu, and as Yagura evade it he is hit by a kick from Mei but he block it with his club with uneven sized hooks and a green flower on the larger end, but even then he is blow away by the kick strength and soon after Mei went after him.
Meanwhile Mangetsu, a men with purple eyes, shoulder-length, white-coloured hair and pointed, shark-like teeth that wears a of a black, sleeveless shirt, light-purple-coloured pants and striped leg-warmers typical of his village, carries a water bottle attached to a belt around his waist and wore bandages around his neck and the standard Kirigakure forehead protector was hit by Kubikiribōchō but thanks to his Suika no Jutsu (Hydrification Technique) the sword passes through him without dealing any damage, but Zabuza who was expecting that sent a strong jet of water using the Suiton: Suidan no Jutsu (Water Release: Water Bullet Technique)
And so Mangetsu to defend himself draw Hiramekarei, one of the famous seven swords. Hiramekarei features a wide, flat blade with two curved indentations near its base, creating a sort of cross-guard. Two handles are connected to one another by a short length of cord, earning it the title of "twin sword".
The overall sword looks like a flounder fish in shape. When not in use, Hiramekarei is wrapped in bandages.
As Mangetsu was defending himself, Zabuza use th Mizu Bunshin no Jutsu (Water Clone Technique) to create 3 clone of himself, and use them as a distraction as all of them keep using the Suiton: Suidan no Jutsu to distract and move Mangetsu towards their intended position.
As Mangetsu kept on easily evading and defending he started talking to Zabuza "Look who is back, I thought that the lesson from 7 years ago was enough, but it seem that I made a mistake, after all once again you choose to fight Mizukage-sama...." but as he was talking he didn't notice that he was on the path of the throw Kubikiribōchō that was coming back.
But soon Mangetsu notice it but decide to ignore it and once again Kubikiribōchō pass through him but as soon as it happened he was hit by four jets of water and then he was sent toward a tree were he splashed against it.
As Mangetsu reform himself he heard Zabuza voice that said "I know about your jutsu Mangetsu after all we both were member of the seven swordsman" and Mangetsu replies "That is true, but I also know yours too, and it seem that I have to show you once again why I was the leader of the seven swordsman"
And so Mangetsu says "Hiramekarei Kaihō (Hiramekarei Release" and release the chakra stored inside Hiramekarei that is emitted from the holes at the tip of the blade and rapidly coats the sword in the shape of a really long blue sword, that Mangetsu swing in a horizontal arc as he enlarge his arm using his Suika no Jutsu.
With his long blade Mangetsu was able to hit every water clone of Zabuza forcing them to disperse and it also hit Zabuza but he was able to parry the blow with Kubikiribōchō that finally returned in his hands, but the blow is strong enough to push Zabuza to side as his feet leaves a trace in the ground.
Then Mangetsu shorten the blue chakra blade and then divide Hiramekarei and takes the twin sword form and once again rushes at Zabuza, and the two star exchanging various move but it is Zabuza who is in trouble as while he has to defend every lethal blow that his opponent is sending, Mangetsu can ignore all the physical attack by using the Suika no Jutsu.
Mangetsu with force swings both swords once again enlarging his upper body and Zabuza chose to defend and jump back at the same time, in fact using Mangetsu blow to retreat, and as he was flying back he notice the battlefield was changing and that the ground was now full of water thanks to Ao's Suiton: Suishōha (Water Release: Water Colliding Wave), so he sheath Kubikiribōchō and start doing his hand seal.
And he is done as soon as he land once again on the water and so he unleash his strongest jutsu "Suiton: Daibakufu no Jutsu (Water Release: Great Waterfall Technique)" and a large volume of water is directed from the water on the ground high into the air, once high enough, it cascades down onto the targeted area, resembling a giant waterfall. The force of this waterfall is great enough to hollow out the ground, washing away everything in the area where Mangetsu was.
In the aftermath, whatever remains, appear devastated, as though some sort of natural disaster has just occurred, but in the middle of that devastation there is a big blue shield, that once again takes the form of Hiramekarei and behind it the unharmed figure of Mangetsu who says "That did surprise me a little, it seem that you did improve in these 7 years, but so did I!"
And so Mangetsu briefly enlarge his legs to give himself more speed, and soon appear in front of Zabuza and swing his sword in an upward motion, and Zabuza who was surprise by the unexpected burst of speed was unable to dodge in time "Argth!!".
He luckily was able to evade the lethal blow but his arm holding Kubikiribōchō was cut off, and just as Mangetsu was about to finish Zabuza off, a surge of malevolent chakra is felt and soon after the roar of the Sanbi heard.
Then as Mangetsu was distracted by the sight how the huge Sanbi, Haku suddendly appared behind him and touching the wet ground once again used the Hyoton: Tōdo (Ice Release: Frozen Ground) to create the surface of ice, and froze the feet of Mangetsu only this time used more chakra and also the rest of the body was getting frozen.
And Mangetsu who now is aware of his mistake starts struggling to escape while he yells "What is this?!? I thought that the Yuki clans was extinct..." but soon the rest of his body was frozen and Chojuro who took Kubikiribōchō from Zabuza's cut arm used the flat of his blade to hit the frozen statue of Mangetsu causing to shatter in many pieces.
Then after while Chojuro was making sure that Mangetsu was really dead and to be safer put the shattered pieces in a sealed container, Haku went toward Zabuza and started doing first aid, first by stopping the blood loss of his cut arm then he froze Zabuza arm while he says "You are lucky Zabuza-san, From what Ren told us as long something isn't lost or destroyed he can put it back and heal it, so you will be as good as new, that is if we win"
Then Chojuro comes with Kubikiribōchō in his hand and Hiramekarei on his back, and as he give Kubikiribōchō back to Zabuza he says "Now what do we do?" and while the sounds of the battle against the Sanbi continues, Zabuza takes Kubikiribōchō and replies "Now? We go after that bastard Yagura, but try to recover as much chakra as possible, I'm almost spent, and you?" Haku says "I have one third of hit, freezing Mangetsu took a lot more than usual" and Chojuro "I have more than half"
And so Zabuza say "Then let's end this once and for all....after this I need a drink or two...or three".