The Mizuki Strikes Back Arc is the third filler arc in the original Naruto anime and the second of the Post-Sasuke Retrieval filler arcs.
Short Summary
An old enemy from the past, Mizuki, breaks free from the Konoha Strict Correctional Facility in order to exact his vengeance on the village. The only ones standing between him and the power he craves are Iruka and Naruto, who try to dissuade the madman from his path.
Long Summary
With the mission to the Land of Rice Fields behind them, Sakura and Naruto are ready to begin training in earnest for the future. In Naruto's case, however, the training is put on hold due to Jiraiya receiving a last-minute assignment to gather intel on the Akatsuki organization (information that he withholds from Naruto) and leaves behind a scroll that holds all his training methods. It turns out to mostly be a hoax with only "Guts!" written at the end of the scroll, much to Naruto's horror. With Jiraiya gone and the other Konoha 11 continuing their training, Naruto Uzumaki is stuck on his own for now.
At the Konoha Strict Correctional Facility, a white-haired prisoner finishes his work but not before stealing a tool from a sentinel without his knowledge. The prisoner lures two other convicts, Fūjin and Raijin, to his cell and gives them food which he has been doing for them for a while now. The white-head tempts them further with promises of more tasty food that they can get at his friend's place—specifically Orochimaru. Tsunade meanwhile summons Asuma and Kurenai with disturbing information regarding a formula that was uncovered in her mountains of paperwork. Originally the formula was found with the belongings of Mizuki, who deceived Naruto into stealing the Sacred Scroll for his own power and benefit...or so it seemed. The handwriting on the paper strongly resembles Orochimaru's from the time that he was abducting Konoha shinobi and others to use in his experiments before his defection. Now believing that Orochimaru masterminded the Sacred Scroll incident through Mizuki, Tsunade sends Asuma and Kurenai to the facility in order to interrogate the former instructor on what he knows, with an eavesdropping Naruto not far behind. By the time Naruto catches up, the convicts have all escaped and the jōnin are left badly injured from an ambush set up by the white-haired man, now revealed to be Mizuki.
The timely arrival of the Medical Corp saves Kurenai and Asuma but takes them out of the action. Naruto, now hoping for a lead on Sasuke's whereabouts, decides to go find Mizuki and pump him for information on Orochimaru. He is stopped briefly by Tsunade who wants him to stay focused on missions that would benefit Konohagakure and not go off on a wild goose chase, but then a distressed Tonton interrupts and relays that Shizune and her squad, who were dispatched earlier to trail Mizuki, were ambushed and defeated by the latter including the Legendary Stupid Brothers (Fūjin and Raijin). This only intensifies Naruto's desire to find Orochimaru and takes off with Tonton leading the way. Kakashi arrives soon after carrying a pair of escapees asking what Naruto has gotten into this time. After a briefing, Tsunade has to send Kakashi away on another mission so he won't be able to help further. He leaves behind Pakkun to assist with the tracking of Mizuki just as Iruka, who witnessed Naruto and Tonton heading out, walks in to give his report. He is then ordered to go aid his former student in rescuing Shizune.
Mizuki and the brothers arrive at a house on the outskirts of Konoha and meet with Tsubaki; Mizuki's ex-fiance. Tsubaki makes new outfits for the trio and tells Mizuki that the village has changed while he was imprisoned. When Mizuki states that he intends to go to Orochimaru, Tsubaki tearfully begs him to reconsider due to all the losses that were sustained during Konoha Crush because of the former Sannin. She also calls him out for lying about Naruto being a monster, which makes Mizuki snap and declares that Konoha is beyond idiotic for even acknowledging the boy at all. Mizuki shows how his mental state has decayed by laughing that Konoha will soon be his once he obtains Orochimaru's power while adding that he and Tsubaki can have the life they always wanted. Tsubaki begins to cry when she hears this and begs him not to be foolish, only for him to knock her out after faking recompense. Mizuki leaves the house along the Stupid Brothers to continue on towards Otogakure, making use of their prisoners' garbs in order to throw off Konoha's trail and to potentially lead them into a trap. Surely enough, Naruto and Tonton stumble upon the uniforms and are joined by Iruka and Pakkun soon after. Tonton is sent back to the village with the remaining three moving on and coming across Shizune who explains that she was attacked with her men still in pursuit. The group continues onward with Pakkun picking up the scent of convicts which leads them into Mizuki's trap. It's revealed that "Shizune" was Mizuki himself which Iruka correctly deduced when his deception didn't match up with typical shinobi protocol (i.e. a team leader is only left behind if they're dead or crippled and also that he didn't argue Iruka's suggestion to get onto higher ground so they could more easily track the enemy). Soon the brothers come out and take on Naruto's Shadow Clones while Mizuki and Iruka take their fight elsewhere. Naruto attempts to follow his sensei but the brothers' herculean strength keeps getting in the way and the situation becomes dire after Fūjin accidentally steps on their lunch thanks to Naruto making them dizzy. The enraged brothers are about to kill Naruto for ruining their meal but soon they are stopped by the Ino-Shika-Chō trio with a Shadow-Possession Jutsu. Naruto and Pakkun go on ahead while the Ino-Shika-Chō team holds the brothers in place.
As Iruka and Mizuki do battle, the latter demonstrates a wide array of jutsu such as Earth Style, puppet jutsu, and even layering genjutsu on top of real techniques. Iruka repeatedly tries to dissuade his former friend from the path he has taken, saying that they are still comrades and have the Will of Fire in their blood plus that his varied abilities could be of better service to Konoha, but it is to no avail. Mizuki cruelly admits that ever since childhood, he'd only been pretending to be Iruka's friend in order to get recognized by important people like the Third Hokage and that he secretly enjoyed seeing Iruka suffer from the loss of his parents. He further explains that his resentment of Iruka only grew after they took the Academy Teaching Exam which resulted in the latter passing but not the former. This was due to Mizuki killing a former teammate on a mission to recover a document due to a leg injury the man received while fleeing from an enemy; Sarutobi and the exam proctors made this a point to hold him back until they were certain he wouldn't do it again. Though Mizuki was eventually passed, his anger at not making the initial cut coupled with the fact that Iruka, whom he felt wouldn't have passed without his help, did caused him to lose all respect for his friend, the village and the Will of Fire in general, believing things such as camaraderie and loyalty were worthless concepts and that power and accomplishing missions were all that mattered. On the night he killed the injured man, Mizuki was approached by Orochimaru, who had witnessed his transgression, and was given a curse mark on his right arm.
Seeing that the man is too far gone and refuses to atone for his crimes, Iruka hardens his heart to properly battle Mizuki within the very same building that they first took the Teacher's Exam long ago. Mizuki's familiarity with dark surroundings gives him the edge with Iruka barely able to keep him at bay even with the latter's sensitive hearing. Eventually, he hears paper bombs about to go off with Naruto and Pakkun arriving just in time to see the building being destroyed. Tsubaki, who had been tailing Mizuki, arrives and helps Naruto dig Iruka out of the rubble. She begs them to let her accompany them in order to stop her ex-lover from going to Orochimaru.
Meanwhile, Tsunade is still pondering the paper from earlier when Tonbo Tobitake informs her that Mizuki raided the Nara Clan Research Facility and took some ingredients; namely the same as described in the formula. Just as she begins putting the pieces together with the ingredients, Iwashi Tatami comes in and informs her that only Mizuki, Fūjin, and Raijin are still at large from the breakout and that the three were seen leaving together. A horrified Tsunade leaves to go after the criminals upon hearing this; realizing that the Ino-Shika-Chō trio is out of their league. As she suspects, even while pinned down with the Shadow Possession and Partial Expansion jutsu, the Legendary Stupid Brothers' sheer strength is able to put up some decent resistance and can even Ino's jutsu does little good. Thankfully Tsunade manages to get to where they are just as the trio's chakra runs out and paralyzes the brothers with genjutsu. They react with fear and familiarity with the Hokage, indicating a prior encounter with her, and she bests them with a couple of forehead-flicks. Cowed into submission, the brothers apologize for their wrongdoings and agree to return to the facility in exchange for dinner while Tsunade and Team Ino-Shika-Chō get back to pursuing Mizuki.
Mizuki follows the instructions left by Orochimaru and enters a cave where he proceeds to mix a potion from the ingredients he stole. As Naruto and company approach the cave, Tsubaki explains that she knew about Mizuki's association with Orochimaru for a long time and that her ex was planning to give the Scroll of Sealing to him as an offering. She was fearful of the consequences if his true objective ever came to light and didn't tell Konoha, which Iruka and Pakkun admonish her for. Tsubaki apologizes to Naruto for Mizuki's manipulations from back then but the latter doesn't feel resentful due to giving the man what he had coming right then and there. Naruto does believe that the chūnin may have a link to Orochimaru's whereabouts, and by extension Sasuke's, and wants to pursue that reason.
The group arrives at the cave just in time to see Mizuki consume the liquid he made and mutate into a tiger-like form, determined to kill them all. Tsubaki's begging does nothing to sway her ex-lover and he even tells her that she's useless to him before he bats around Naruto and Iruka. He attempts to kill Iruka with a giant shuriken like in their last fight but this time, Naruto shields his teacher from it, even telling Mizuki the same thing as before (that he'd kill Mizuki if he ever tried to harm his sensei). The madman laughs at the irony of it all before declaring that he's different now and uses his curse mark to further change into a tiger-like state. While this increases his strength significantly, Pakkun notices that he converted most of the chakra he used for speed into the form and thus has become sluggish. Iruka hatches a plan while Naruto asks Mizuki where Orochimaru is, letting him know that Otogakure was abandoned by the Sannin. Mizuki, however, thinks that Naruto is just making excuses and keeps attacking. Seeing the gleam from his sensei's headband lets Naruto in on the plan and lures Mizuki to the spot where a Seal Binding Formation is waiting. Now paralyzed, Mizuki can do nothing to defend himself against Naruto's Rasengan and is taken down.
Soon after his defeat, Mizuki's tiger form withers away into an old husk of his former self with him coughing up blood. Mizuki accuses Naruto of ruining his body but Tsunade comes along with the Medical Corp and informs everyone that the animal potion's effects were just temporary before the burden on the cells becomes too great, thus causing them to be destroyed. The tiger curse mark was only a byproduct of Orochimaru's jutsu development and he never had any intention of using it in the field, let alone bringing Mizuki into his fold. Thus Mizuki's bond with Orochimaru is severed, Tsunade saying that even with the best treatment, the former-mentioned will never be a shinobi again. Iruka expresses to Naruto how unfortunate this is for finding Sasuke, but Naruto isn't too upset and is still determined to bring his friend back to Konoha someday. Shizune was found earlier and will pull through while Tsubaki resolves to start her life anew after she atones for putting the village in danger. As the medical ninja attempt to stabilize him, Mizuki curses that one day he'll be back stronger than ever to kill Iruka and Naruto, but Iruka tells him off by saying that Naruto has been gaining true strength every day and that Mizuki will never catch up to him now. As they head back to the village, Sakura comes to tell her mentor that she's mastered the first phase of training, impressing Tsunade. Meanwhile, a proud Iruka muses that Naruto saved him this time and that the boy will continue to get stronger in the days to come.
The Mizuki Strikes Back Arc has the following tropes:
- Adaptational Badass: Mizuki went from being a chūnin with shuriken proficiency in the manga to a cunning psychopath who is proficient in everything from Earth Style to basic ninja puppetry.
- Adaptation Expansion: The arc's opening scenes come from Part I of the manga and are utilized here as setups for the arc's starting point:
- All the scenes showing the Konoha 11 (sans Naruto) hard at work training (Sakura healing a fish, Kiba walking Akamaru while Shino sulks, etc.) are used here as a hilarious subversion to Naruto thinking his training with Jiraiya was going to start right away only to be informed that the pervy sage has to leave.
- The scene with Shikamaru and the Sand Siblings was greatly extended with mention of the latter team teaching at the academy while they stayed there (offscreen) during the last arc. The students see them off alongside Shikamaru with Moegi saying that
she wants to be strong like Temari someday. - Iruka's flashback to Hiruzen telling him about the Will of Fire is expanded to include a young Mizuki eavesdropping on them, deciding to use his friendship with Iruka to gain favor with the Hokage. Judging from the old man's expression, however, it's doubtful he was fooled.
- Adaptation Relationship Overhaul: In the first arc, particularly the manga version, there was nothing implying that Iruka and Mizuki were anything besides fellow teachers who ended up being enemies due to the circumstances at play. At one point, Iruka even called Mizuki a scumbag without a hint of pathos. Here they're mentioned to have a friendship that stems from childhood (at least from Iruka's point of view) and the former showcases plenty of angst and resignation about Mizuki's downfall.
- Adaptational Villainy: As bad as he was before, at least Mizuki's manga incarnation was never inferred to be in league with the likes of Orochimaru.
- Adaptational Heroism: On the other hand, he's also shown to have had a fiance at some point, while the manga never implied anything of the sort. Downplayed as it becomes clear that Mizuki at best only views her as a potential Trophy Wife and turns violent once he realizes that she lacks his ambition.
- A Day in the Limelight: For Iruka and arguably Mizuki. This arc is one of the only times we see Iruka take an active combat role.
- Axe-Crazy: Mizuki showed signs of it in his original appearance, but after some time in prison, he's long since stopped holding back with this one.
- Berserk Button: Don't cause Fūjin or Raijin to step on their lunch. Also, if you encounter them wandering around the prison, you'd better have something to feed them or it will get ugly.
- Beyond Redemption: Iruka and Tsubaki both find this out the hard way when they meet Mizuki again.
- Big Damn Heroes: Team 10 saves Naruto just as he was about to be pounded into dust by the Legendary Stupid Brothers.
- Later on, Tsunade of all people pulls this to the above-mentioned team by making Fūjin and Raijin crap themselves in fear.
- Body Horror: When the tiger potion loses its potency Mizuki withers away to a shriveled old man that's nothing to behold.
- Call-Back: Naruto taking a shuriken to the back for Iruka and telling Mizuki off for it is an in-universe example to the beginning of the series' very first story when Iruka did the former for his student. Mizuki jokingly refers to it as "a play" in one translation saying that nothing ever changes.
- When suffocating his fallen teammate, Mizuki refers to the man as a ball and chain (or deadweight) to the squad, just as Arashi did to Sakura in the previous arc.
- Tsunade mentions that a chūnin on his own (Mizuki) wouldn't be able to make much of a sealed scroll's power, similar to how Aoi Rokushō from the Land of Tea filler needed Ibiki, a jōnin, to unseal the scroll he had Idate steal for him.
- The entirety of Iruka and Mizuki's fight has shades of Naruto and Sasuke's battle at the Valley of the End with the former trying to persuade the latter from turning his back on Konoha.
- Clipped-Wing Angel: Mizuki's second state curse mark turns out to be this, decreasing his speed and making him easier to entrap. It proceeds to destroy his cells and leaves him a broken old man, costing him all of his abilities as a ninja.
- Death Glare: It's hard to notice with everything else surrounding it but after Mizuki makes himself known in the flashback, Hiruzen's smile fades and he continues the long face even when Iruka and his "friend" happily head off. Given what Mizuki reveals to Iruka later, it's likely the old man knew that the boy was a bad seed from the start which may have also played a part in his decision not to hire him as a teacher.
- The Ditz: The Legendary Stupid Brothers are this to a tee. For instance, Raijin wonders why his pinky is weaker than his thumb, and Fūjin's response? "If the pinky were as big as the thumb, then your thumb wouldn't be special anymore!"
- Dumb Muscle: Fūjin and Raijin are none-too-bright but have amazing levels of strength that prove an obstacle to Naruto and Team 10. As Pakkun puts it: stupidity is a powerful thing.
- False Friend: Mizuki tells poor Iruka that ever since childhood, he enjoyed seeing Iruka suffer and pretended to be his friend in order to get attention from the Hokage and others.
- Fat Idiot: Fūjin and Raijin.
- Greater-Scope Villain: As with the last arc, Orochimaru can't seem to keep his coils out of Naruto's way. He gave Mizuki the curse mark just to see if it would pan out and is inferred to have had a hand in the attempted theft of the Sacred Scroll, harkening back to the very start of the series. In this case, the joke's on Orochimaru since he indirectly played a part in shaping Naruto's beginning as a ninja through Mizuki.
- Green-Eyed Monster: How Mizuki's disdain for Iruka began; he was tired of all the attention that Iruka received due to the death of his parents.
- Hulking Out: The first stage of Mizuki's curse mark causes this.
- Hypocrite: Mizuki says that at one point, he did care about Konoha and keeping it safe, but every action he takes contradicts that claim. He suffocated his teammate to ensure that no information would fall into an enemy's hands yet he is shown taking pleasure in snuffing the poor guy out. Later still, upon overhearing the Hokage's reasons for not passing him on the Academy Teacher Exam, Mizuki takes offense and grows resentful of Iruka even though he later got the position anyway as we see in the first chapter/episode of the series.
- All in all, camaraderie and loyalty are looked down on by Mizuki as nothing but a distraction from true glory. This coming from a guy who was raised in a village that believes in cherishing one's friends and loved ones and also that bringing every one of your squadmates home safely is a victory in itself. Interestingly, this is the one vice that no one in the arc, not even Iruka, calls Mizuki out on.
- I Can Change My Beloved: Keep dreaming Tsubaki...
- Inferiority Superiority Complex: Mizuki was torn up over not being recognized by his capabilities and damningly tells Iruka he will never acknowledge him as a true shinobi.
- I Just Want to Be Special: Mizuki's motivation boils down to this, but ends up going about it the completely wrong way.
- I Reject Your Reality: Inferred with Mizuki calling Konoha stupid for amending their opinions of Naruto, clearly still sore after the beating he received from the boy.
- Mega Neko: Mizuki's curse mark invokes a tiger theme.
- Might as Well Not Be in Prison at All: So great is the strength of Fūjin and Raijin that they routinely bend the bars to their cell and walk around the facility looking for food. Any guards they come across run the risk of evoking their wrath should they have no food.
- Morality Pet: Tsubaki appears to be Mizuki's at first, but Mizuki quickly decides that he doesn't want her anymore when she calls him out about his prejudice against Naruto.
- Noodle Incident: We're never given details about what happened between Tsunade and the brothers to make them fear her so much. Shikamaru doesn't want to know.
- Plucky Comic Relief: Villainous variation with the Stupid Brothers; they do help out Mizuki for the first half of the arc but are mainly there just for humor and to take the piss out of Naruto's fighting style i.e. using Shadow Clones for most of it.
- Put on a Bus: Jiraiya departs for the foreseeable future on a mission to gather intelligence on the Akatsuki, as given to him by Tsunade. Aside from flashbacks, cameos, and a couple of guest appearances, he's pretty much gone until Part I of the anime's end.
- The Sand Siblings return to their village and won't be seen again until the Ultimate Weapon arc; the final pre-Shippuden filler (though Gaara and Kankurō do return for the second movie, at least).
- Retcon: Back at the beginning of the series, Mizuki desired the Sacred Scroll for his own benefit and used Naruto to get it for him since he believed that everyone in Konoha would be grateful to have him gone. Not to mention, there wasn't much if any indication that Iruka and Mizuki shared much of anything beyond their jobs as academy instructors let alone a brotherly friendship. Now here, it's stated that Mizuki was stealing the scroll to get into good graces with Orochimaru and that his betrayal of Konoha left Iruka distraught with the latter pleading for his friend to atone and face up to what he's done.
- Secret-Keeper: Tsubaki kept Mizuki's involvement with Orochimaru a secret for years, even against her better judgment. She quickly comes to regret her decision.
- Sequel Episode: This entire arc was one to the first episode of the series, giving Mizuki some deeper characterization and bringing him into conflict with Naruto and Iruka again.
- Supporting Protagonist: Like the last arc, while Naruto does see plenty of the action and delivers the final blow, it becomes clear that Iruka is the true protagonist of the arc. It is Iruka who has the most interaction with Mizuki and the one who tries to get him to see the light and later resigns himself to bring his ex-friend in, whereas Naruto just wants to ask Mizuki about where Orochimaru is hiding. In fact, the latter-mentioned Konoha ninja says that he no longer has any grudge since he beat the tar out of Mizuki back when he did; a rare form of maturity we don't usually see in the series' filler.
- Took a Level in Badass: Ino learned the Mind-Destruction jutsu at some point which she uses on Raijin to attack his brother. It doesn't do much, but still...
- Took a Level in Jerkass: Mizuki was no saint in his debut but here he's crueler than ever, especially when mocking Iruka about their false friendship.
- Villain Forgot to Level Grind: Downplayed; Mizuki did come back stronger than before, but Naruto had already long surpassed him by that point.
- Villainous Glutton: Guess who? It's stated early on that Fūjin and Raijin murdered their own squadmates over a meal they wanted and were barely able to be restrained when they were arrested. It's mostly something edible on their minds.
- Villain Protagonist: Mizuki can be seen like this in some parts of the arc as his actions are given a bit more focus than your typical filler villain. Most of the penultimate episode barely has him talk at all and focuses on him gathering the materials for his curse mark to activate. It probably helps that he's a canon character from the manga and the audience gets to find out more about what makes him so evil.
- Walking Shirtless Scene: Mizuki and the Legendary Stupid Brothers; courtesy of the new clothes Tsubaki made for them.
- We Can Rule Together: At first, Mizuki suggests that he and Tsubaki can have the life they always wanted once he gets Orochimaru's power, but quickly changes tunes when she doesn't go for it.
- The Worf Effect: Asuma, Kurenai, and Shizune get taken out of the action early on to show just how much Mizuki has changed since his imprisonment. Fūjin and Raijin are subjected to this at Tsunade's...finger flicks after brawling their way through Shizune's squadron, Naruto, and Team 10.
- You Could Have Used Your Powers for Good!: One of Iruka's arguments is this when he sees how well versed Mizuki is with ninjutsu. It falls on deaf ears, of course.
