For reference, the entire "The Festival" - Arc took place about six years after Anko's departure.
Let's start this from the beginning
Ryūchi Cave
1 month after leaving Konoha
Anko had no illusions about the odds of her actually finding Ryūchi Cave. In all likelihood, she would either spend the rest of her life searching for it or give up on this endeavour after some years and return to Konoha as a failure. There simply was no in-between.
But she also realized that this was the only way that might save her from being left behind.
She herself had been called talented, prodigious even, since her earliest childhood. That was why Orochimaru, one of Konoha's most powerful shinobi, had been willing to take her as an apprentice. And while it never came to that because it turned out her sensei was a slimy bastard who fled the village when it came out that he experimented on humans and even babes, the point still stood that someone of his calibre saw enough potential in her to warrant personal interest.
However, whatever talent she possessed paled compared to Itachi's. Next to him, she was average at best. That wasn't even an insult; being called average compared to someone who could do what Itachi did when he was just seven years old was in fact a compliment.
That didn't change the fact that Anko didn't want to fall behind him, though.
He, Yukio, and she were teammates. They were supposed to have each other's backs. Especially now after Yukio had confessed to her that he considered giving up on being a shinobi altogether was it important that she got strong enough to cover Itachi for them both. Sure, she knew that the younger boy had other friends as well, members of his clan that would look out for him if she couldn't, but Anko wasn't about to give up that easily. No, the only path she accepted for herself was one where she became strong enough to stand at his side.
Teams were like a family, especially those that had been formed between academy graduates, and while Itachi had joined them only later, he was just as much part of it as Yukio, Tanaka-sensei, and she herself. In her case, they were literally the only family she ever had, so there was no way she would become a burden.
Furthermore, Anko still intended to get revenge on Orochimaru for his betrayal. The Sannin was far stronger than any other enemy she had ever fought, and she knew that she didn't stand a chance against him as she was now. If she were completely honest with herself, she would probably never stand a chance against him either if she didn't take extraordinary steps to improve herself. The Chūnin Exams demonstrated how strong even enemies her own age could be; if she couldn't even beat them, how could she ever hope to bring Orochimaru to justice?
The best solution to all her problems was to find Ryūchi Cave and train under the White Snake Sage. That was unfortunately easier said than done, however.
Anko had even tried asking her summons to lead her there, but just as she had expected, they had refused. Apparently finding the way on their own was part of the test anyone who wanted to train under the sage needed to pass.
That meant she had no other choice but to wander through the continent with no clue whatsoever whether she was getting closer or not, basically hoping to just randomly stumble into it.
They're still snakes, she thought. That means they can't live just about everywhere. The climate must meet certain conditions to be a potential home to them, so I can exclude at least some places. Not nearly as many as I would like, but it's a start.
Who knew? Maybe she was lucky and really just ran into it within a few weeks. Now, wouldn't that be something?
3 months after leaving Konoha
Unfortunately, she was not so lucky.
With no other choice left, Anko decided to begin her search within the borders of the Land of Fire. The idea was that she would at least not need to deal with enemy shinobi this way. If she didn't find the cave here, however, she would be forced to look elsewhere and therefore enter foreign countries.
She really didn't look forward to hiding from patrols all the damn time.
The problem with searching for it in the Land of Fire was that there were a lot of places far enough away from any hotspot of civilization to possibly hide the cave. And as the entire country offered great conditions for snakes, Anko couldn't even limit the area she needed to look by taking that point into consideration.
The best thing she could do was asking in small, local villages and towns whether they had noticed an unusual number of snakes or if there were any folktales about them in the region.
So far, her search hadn't yielded any results yet. No, the only things Anko had found were countless insects that decided to nest in her sleeping back and hair as well as a newfound appreciation for baths.
9 months after leaving Konoha
She had known from the very beginning that there wouldn't be much for her to do during her travels, but Anko noticed mere days into her journey that it was even more boring than she could have ever predicted. Thus, with no other choice if she didn't want to die from boredom, she did the one thing she had always hated to do:
She studied.
Now, don't understand her wrong. She did study a lot in her life. The expectations that she and later Orochimaru set for herself didn't allow Anko to slack off. However, she initially was content with just mastering whatever was expected of her and never expanding on that on her own, the only "recent" exception being when she went out of her way to create a poison that wouldn't easily vaporize in flames for the Chūnin Exams.
This far away from home, with no one to keep her busy and nothing else to do, she burrowed herself once again in her studies.
Fortunately, the Sandaime had allowed her to bring copies of Orochimaru's notes with her. That, together with various books she brought, she could keep herself at least somewhat busy during her journey. And honestly? Once she actually began to read, she found it quite interesting. Sure, a lot of her former sensei's experiments described in the notes were disgusting, but there was no denying that the information he got out of them were ground-breaking. If you asked Anko, the least thing they could do was to use this information to do something good with them and maybe give the victims some peace in the knowledge that their suffering wasn't for nought.
Furthermore, if this information somehow helped Anko in ultimately bringing Orochimaru down, they would also indirectly get their revenge on him through her. She knew that if she were in their position, she would like that idea.
Unfortunately, no matter how hard she tried to take her time going through the various materials, there came a point where there was nothing new left for her to read. Even writing her own notes down and cross-referring between the different sources only slowed her down that much.
I probably should buy some more books, she thought. Let's hope the next bookstore I find actually has something useful to offer rather than just fictional stories.
Though to be honest, Anko would probably get some of these as well. Not like she had anything better to do anyway, and even a mediocre story was still better than staring holes into the air.
With that in mind, she continued walking westwards until she finally crossed into the Land of Rivers.
1 ½ years after leaving Konoha
The highlight of every day was doubtlessly the training session in the evening. And although it was almost impossible to increase your own Taijutsu skills by training on your own, Anko found a few ways she could improve herself even in face of that.
For one thing, she began to wear weights. She wasn't so stupid as to overdo it like that weirdo Guy, of course, but she was confident that they would increase her speed and strength over time. If she continued to increase the burden little by little and if her search continued for as long as she feared it would, there should be quite the improvement when she finally returned to Konoha.
Another thing she did was to train with her clones. However, the only thing they were really good for was to test new techniques because in the end, they were exactly as strong, fast, and skilled as she was. Handicapping herself made up for that somewhat, but even that wasn't enough to truly help her train.
Anko also tried to incorporate new attacks into her katas by looking for inspiration in the various books and notes she had with her. Whenever she stumbled over a weak point in the human body that none of her attacks already targeted, she tried her best to change that.
Concerning the other ninja arts, well…
Genjutsu had never been something she was interested in. Training with Itachi meant she was forced to learn combatting it and it had also allowed her to pick up a thing or two about it as well, but that was it.
The thing she could train best was Ninjutsu.
There were quite a lot of Jutsu she technically knew but had never mastered, including but not limited to techniques she had seen Orochimaru use before he became a traitor. Now that she had so much free time at hand, she spent countless hours trying and eventually mastering as many of them as she could. There was quite a few of them she didn't get the hang of, unfortunately, and she assumed she would never be able to master them without someone else directly teaching them to her, but those she did master quickly became powerful aces in her arsenal.
Another thing she could also train even as she travelled was the speed with which she weaved hand signs. It didn't cost her any chakra, was something she could do practically all the time, and kept her hands busy; all in all, she counted this as an absolute win.
At this point, she was quite confident that everyone who didn't possess the Sharingan would struggle to predict what technique she was to unleash on them. That should give her a little edge even against otherwise superior opponents.
However, no matter how much Anko improved, nothing could distract her from the fact that she had been away from her home for 18 months now and still had nothing to show for it. It was one thing to be prepared to spend years on the road but something entirely different to actually do it.
It might have been easier to endure if she could at least communicate with her friends, but alas, the best thing she could do was sending them letters. Receiving them in return was pretty much impossible, though one of Itachi's crows had managed to find her once.
With a sigh, Anko cast these dark thoughts aside and continued her journey northwards, forming hand signs all the time.
3 years after leaving Konoha
She was a few miles away from the border to the Land of Wind when she saw a large cloud of black smoke rise into the sky.
Now, this was a foreign land filled with foreign people. Anko had no duty to anyone that lived here, nothing that would force her to intervene in whatever was going on. That being said, she also knew that this region of the Land of Rivers was poor and far away from the nearest city. It was unlikely that any other aid would arrive in time to help the people living here.
Without hesitation, Anko began to run.
It wasn't before long that she began to hear people screaming, though were it just that, she might have continued to hope that all she was going to find were people trying to extinguish a house that had caught fire or something like that. However, Anko was unfortunately all too familiar with the sound of crashing metal and the crazy laugh of men that enjoyed the slaughter of innocents, so she had no illusions regarding what was happening.
Her expectations were met a moment later when she came into sight of the little town:
People in tattered and flicked clothes ran for their lives while brutish looking men hunted after them, swinging their weapons above their heads and hollering jeers and insults towards their prey. There were already countless corpses spotting the area; from old men to mothers with their children, no one had been spared so far and Anko doubted the assailants planned to change that approach any time soon.
Anko had no intention of being any more merciful with them than they were with the townspeople.
She didn't know how many enemies there were, but it hardly mattered. None of them appeared to be shinobi and thus none of them was a threat to her. So, confident in her own superiority and with anger burning in her stomach, she jumped into the fight.
The first few bandits didn't even realize what was going on before they died. Two of them were running after a young girl with what must be a younger sibling in her arms when Anko appeared next to him and drove a kunai through his throat. The other one was a few steps behind and too close to stop, so before his brain even caught up with the events, she took the fallen bandit's rusty sword to end his comrade's life with it as well. Instead of stopping there, she spun around and threw the weapon, instantly killing a bandit a few dozen meters away that was just about to do the same to an old man that sat on the ground in front of him.
"Kage Bunshin no Jutsu!" (Shadow Clone Technique)
Half a second after making the necessary hand seals, half a dozen versions of her rushed into different directions to save as many people as possible.
One man that had cornered a girl in an alley suddenly found his head bashed against the stone wall to his right before being thrown backwards into one of his comrades. Befuddled as he was by the attack, he didn't even get to scream before a fireball consumed them both.
Another group of five were running after a family of three when Anko appeared between the two parties; the bandits, not judging her a threat, only laughed harder and rushed at her, making it all the easier for her summoned snakes to kill the first four by sinking their fangs into their throats. The fifth one, being fortunate enough to be a bit behind, managed to come to a stop before the same could happen to him, but he was still too slow to dodge the kunai that sunk into his forehead a second later.
A few smarter ones were realizing what was happening and tried to flee, but all it took to stop them was a simple earth wall to block their path. None of them survived long enough to search for another way out.
However, she and her clones didn't just target the aggressors but also helped the residents.
An old woman buried under some fallen over cart had already given up hope when Anko appeared and pushed the vehicle off her.
A young couple trapped in a burning building and almost unconscious from all the smoke cried in relief when she broke through the wall, extinguished the flames in their path, and then carried them to safety.
The most challenging thing that happened was when she found a middle-aged man with a slash wound on his chest; he was still alive and the injury wasn't as bad as it could have, but it was still the worst wound she had ever attempted to heal. Never had she been more thankful for reading the notes Orochimaru had left behind, as for all that many of them contained gruesome content, the information regarding how to keep prisoners alive for as long as possible while experimenting on them could also be used for situations like this.
I should try to get my hands on some real books about healing, though. Who knows when that will become handy.
In the end, Anko couldn't save everyone. She appeared too late for that. But even if she had arrived earlier, she couldn't be everywhere at once, so she decided to be grateful for having been able to help as many as she did instead of crying for those that had died. It was thanks to her interference that there were still enough people left to rebuild, so it wasn't as if nothing good came out of this. The people would mourn for the dead, yes, but they would recover and continue to live from these lands as they had done for generations.
None of the bandits survived, of course.
[][][][][]
Anko stayed at the destroyed town for almost a week to help with burying the corpses, rebuilding the houses, and healing the injured. She didn't need to, but she did it anyway.
She was rewarded for that in the end when it turned out that one of the townspeople, an old man that once travelled the continent as a merchant, knew a housewife's tale about "a kingdom where gigantic snakes rule supreme" he was more than willing to share with her.
It wasn't much, but considering it was also the first real clue she got, Anko was unsurprisingly excited to continue her journey.
She departed the very next day.
4 ½ years after leaving Konoha
The Land of Birds wouldn't have been her first guess regarding the location of Ryūchi Cave. Nonetheless, once she was there, she became more and more convinced that she was getting closer and closer.
The country was located between the Lands of Earth and Wind, but it had much more in common with the former than the latter. The main difference, however, was that instead of being spotted with rocky mountains and bare hills everywhere, the mountains here formed hundreds of valleys with abundant vegetation and dense forests.
Befitting its name, there were also birds everywhere. Day and night, their twitters could be heard no matter where you were, almost driving Anko crazy with their constant noise. It took all the self-control she had to not constantly kill every bird she got across.
The problem was that the area made it extremely hard to effectively search for that stupid cave. Ever since she managed to get here a bit over a year ago, escaping Suna patrols that weren't happy about an unknown stranger in their lands in the process, she fought her way through almost impassable mountain ranges and all-encompassing forests, but no matter how hard she tried, progress was slow.
Anko was just about to cut her way through some particularly stubborn undergrowth when her body reacted on instinct and jumped aside, saving her of the unpleasant experience of having a snake plunging her fangs into her ankles.
"Hey," she exclaimed angrily. "What did I do to you, asshole? Leave me alone!"
Initially, she had been happy about the insane number of snakes in the country and took it as confirmation that she was close to her goal, but she quickly grew annoyed at them for constantly attacking her. Were she not afraid of offending the White Snake Sage, she would squash every single one of them.
Fortunately, the snake did what she told it and slithered away after one last hiss.
Unfortunately, it was only then that Anko realized that the snake had been bone white.
"Dammit!" she cursed under her breath before hurrying in the direction the snake had vanished. "Hey, come back! I didn't mean it like that, I promise!"
For all that she had seen thousands of snakes since entering this country, this was the first time she had seen one with that specific colouring. In fact, this was the first time seeing a white snake since Orochimaru had left the village. Now, that could just be a coincidence, of course. Albinos were after all known to plop up from time to time. However, if what Anko believed was true, this snake might actual lead her to Ryūchi Cave.
Its unique colour had the advantage that it stood out from the rest of the environment and thus allowed Anko to spot it a few seconds into the hunt. That should have been the end of it; after all, there was no way that a small snake like that could escape a shinobi like her. However, to Anko's neverending frustration, the thick vegetation meant she couldn't move as quickly as she would have liked to while the snake with its smaller body could easily wriggle through obstacles without even slowing down.
Anko let out a frustrated cry as she jumped straight through some brushwood, ignoring the way its branches shredded her clothes and cut through her skin. All that didn't matter to her as long as she managed to keep her eyes on that annoyingly nimble snake.
She had no idea how long she ran after it, but when she finally broke through the treeline into the open just a dozen metres away from the wall of one of the mountains that encircled the valley, her entire body was covered with scratches. It had been worth it, though, as she had managed to stay close enough to her target to see its white form vanish into a nearby tunnel.
"Gotcha!" She immediately rushed after it, excitement bubbling in her chest at the thought that this was it, only to come to an abrupt halt when she crossed the entrance and came face to face with a veil of darkness and, more notably, a lack of white snakes. "Oh, c'mon! Seriously?"
Seeing no other way, she slowly walked in. Running would have naturally been preferable, but no matter how anxious she might be, Anko wasn't stupid enough to run when she could barely see her own hands in front of her face. Walking in into what could possibly be the lair of some predator like this was stupid enough, no need to risk falling to her death because she overlooked some hole in the ground.
She wandered through the darkness for what felt like hours, though it were probably only minutes. Anko had no way to know for sure, however; keeping track of time in such an environment was almost impossible. Then, when she finally saw light at the end of the tunnel, she was disappointed to note that what was on the other end was not the fabled home of the White Snake Sage but just another valley.
The white snake she had followed hadn't made another appearance either.
However, what made this valley at least somewhat interesting was the modest housing that stood barely a hundred metres from her position at the exit of the tunnel.
This wasn't the first time she had encountered people in this country, of course. For all that it was relatively sparsely inhabited, there were villages and towns, and while she hadn't been there herself, she knew that the capital was said to be rather impressive. All that being said, most of the lands were firmly in the hands of nature. Anko had spent over one year here and so far only found one single village and half a dozen families living on their own at remote locations.
Decision made, she moved towards the building with deliberate steps. She didn't have any trouble with the people of this country yet, but in her opinion, no one who lived this far out here on their own could be completely sane. Humans simply needed some contact with other humans if they didn't want to wilt away.
Her attention snapped to the door when a person stepped out.
"Oh my," the woman said with a friendly smile. "What a wonderful surprise! It has been a while since we had a visitor. Say, what are you doing here all on your own, my dear? Don't you know that it's dangerous to travel all on your own?"
The woman appeared to be in her late fifties, with hair that was more grey than black and a forward bent stance. She wore simple black robes that were stitched at several places and going by the calluses on her hand and the sun-kissed, wrinkled skin, she had spent a lot of her life outside.
All in all, she looked just like every other inhabitant of this country she had met so far.
Furthermore, while she tried to hide it, Anko could see the tension in her limbs and the apprehension in her eyes; everything pointed at her being afraid of Anko and what she would do to her. Not unreasonable considering civilians were pretty much defenceless against a shinobi. There was nothing this woman could do to stop Anko if she had bad intentions.
"I can defend myself just fine," she replied, making sure to stand as unthreatening as possible while keeping her voice calm. "I'm just exploring the region and stumbled over your home by accident. I mean no trouble."
The woman relaxed. Anko could be lying, of course, and she obviously did, but she had no need to trick her as she was already superior in every single aspect. To her, that meant that Anko must be telling the truth.
"Exploring the area? That must be so very exhausting! Our country is lovely, but the vegetation and all these steep hillsides…" She shook her head. "These days, we can't even travel to the nearest village on our own anymore."
"I'm terribly sorry," Anko said as sincerely as she could. "That sounds very harsh."
The woman waved her off. "Oh, don't you worry, my dear. You get used to it. Now, why don't you come in, clean a bit up, and let us give you something to drink? It's such a hot day and -forgive us for pointing that out- you look terrible."
Anko looked down her body to see that running through the underbrush in her pursuit of that white snake had done more damage than she initial thought; while the scratches themselves were harmless in and of themselves, there were a lot of them. None has bled too much, but as she was literally covered in them, her clothes were full of bloodstains.
And anyway, she thought as she looked upwards with a frown. It is very hot today. I must have been too distracted by that snake to notice, I guess.
"I would really appreciate it, ehm…"
"Our name is Tagorihime, but please, call us Obaa-san."
She gave the woman a warm smile. "Of course, Obaa-san."
The house was just as modest from the inside as from the outside; there was one large room that seemed to serve as the living space and had one door leading to what Anko assumed would be Tagorihime's bedroom. As there was no other door, you probably had to do your, eh, business, outside.
Anko moved to the middle of the room and sat down on a cushion the other woman's pointed at before gratefully accepting the offered cup of water and taking a large gulp.
"Ahh," Anko sighed in delight. "I really needed that. Thank you, Obaa-san."
She gave her a grandmotherly smile. "Oh, there's no need for that. Now, just wait here while we get you something new to wear. You really can't walk around in such tattered clothes, you know. It's indecent!"
Anko chuckled. "Of course, of course. You're right, it would be really embarrassing if someone saw me like this!"
She would honestly find it more hilarious than embarrassing, but there was no need to say that out loud.
Anko watched Tagorihime move into the adjoining room with an amused smile before redirecting her gaze towards the cup in her hands. She then twirled it for a few seconds with a thoughtful look before drinking the rest of it in one go. For the first time in months, Anko felt truly refreshed and comfortable as a pleasant warmth spread through her body. Finding her sitting position too inconvenient, she first stretched her limbs before burrowing her head onto her arms on the table in front of her. After such a long day, it was probably normal to feel tired, and closing her eyes for a few seconds until Tagorihimi came back shouldn't be a problem, right?
The room stayed silent for several minutes until the owner of the house finally returned. Slowly but steadily, she came closer and closer, the only sound being the quiet creaking of the wooden floor beneath her. Her eyes, previously warm and kind, were now cold and calculating as she lowered her head towards the crumbled form in front of her, mouth wide open and ready to-
Before she had the chance to react, Anko moved and sent a mule kick to her chest.
A second later, a serpentine body crashed against the wall with a 'boom'.
"Seriously," Anko said with a smug smile. "You didn't honestly think I would fall for that, did you?"
Tagorihime, her grandmotherly appearance now replaced by that of a big, black snake with white accents, hissed at her in apparent anger. "You drank the water, I know you did!" Her voice was much higher and shriller than before. "How-"
"Did I?" She took the cup from the table behind her without breaking eye contact and held it in a way that allowed her opponent to see the liquid inside of it. "You really should pay closer attention to your wannabe victims. I hate to break it to you, but it's really embarrassing to fall for someone else's Genjutsu when your own trap is based on one."
The rage the thing's eyes was impossible to miss. "You little-"
"Oh, and by the way," Anko interrupted her before summoning a kunai into her hand and swing it in one smooth arc to her left, seemingly aiming it at empty air. "You also shouldn't try something that already failed a second time, nor fall for the same thing twice. Really, such things make you look like an amateur."
Anko put the cup back on the table before using her now free hand to form a onehanded Ram seal. "Release!"
At her command, her surroundings began to disappear bit by bit while the illusion her opponent had tried to impose on her fell away from her mind like wallpaper peeling off a wall.
The house itself and all the furniture inside it aside from the table behind her with the cup of water faded away, and even the valley it had been located in was replaced by a rocky ground and walls of stone that came together in a roof far above her head. However, maybe the most interesting change was the fact that Anko's kunai no longer pointed at empty air but straight at the yellow eye of another snake. "Impossible!" the brown reptile hissed, its voice much deeper than Tagorihime's. "You saw through my Genjutsu as well?"
Anko shrugged casually in false modesty. "It wasn't that hard. Obaa-san over there referring to herself as 'us' all the time made it kind of obvious that she had either an accomplice or was insane. Being a shinobi and all that, I obviously assumed the former just to be safe." She smirked. "Also, I have a teammate who is much more talented in Genjutsu than either of you two. Compared to his techniques, yours were laughable weak."
Both snakes were obviously -and audibly- unhappy with her statement, but Anko didn't care. What she found much more interesting was the fact that where the tails of both snakes should be, they instead connected with each other, meaning it was actually just a single entity rather than two. "You know, I always thought Amphisbaena [1] were just a legend. Who would have thought you actually exist."
"Not many find their way to us."
"And even less ever have the chance to tell the tale."
Alright, Anko though. I gotta admit, it's kinda creepy if they talk like that.
Outwardly, she chuckled. "Is that so? I take it then that not many pass this little test of yours?" She gave both heads a piercing look. "That's what this is, right? A test to see who can pass and who can't?"
The two heads turned to look at each other -does that mean they can't communicate with their minds?- before simultaneously turning back at her.
"Congratulations, Anko Mitarashi, for you have passed."
"Congratulations, Anko Mitarashi, for you have passed."
As if on command, the earth rumbled as the wall not too far away from her gave way to reveal the entrance to another tunnel, and even from her position, she could feel strong chakra pouring from its other end.
Anko's expression turned into a genuine smile.
At last, she had found Ryūchi Cave.
[1] Amphisbaena: The Amphisbaena is an ant-eating serpent with a head at each end that has its origin in Greek mythology.
In hindsight, the first half of this chapter feels like filler. However, I had lots of fun writing it and I think the second half makes up for it, so I'm gonna keep it like this.
In case any of you are Boruto fans who are just about to write an angry comment to tell me that my version of Ryūchi Cave isn't canon compliant, rest assured that I'm aware of that. However, while I've seen some clips of Boruto visiting Ryūchi Cave on YouTube, I never watched the show and really don't care whether my story is compliant with it or not. I'm sorry if that bothers you, but I suggest you simply consider this as part of the AU and go on with your lives.