A volley of curses rang out behind Sakura as Guren and Kabuto trod on the caltrop-shuriken she'd scattered across the floor. Roused by their cries, a few of the hideout's other residents cracked open their doors as Sakura dashed past, some even joining the chase.
Left, right, right again, left…
Sakura swore under her breath and skidded to a halt, only realising she'd run the length of the latest corridor straight into a dead end. She spun on her heel, hoping the way back wasn't already crawling with Orochimaru's goons… but that, clearly, was too much to ask.
At the sight of the misshapen, curse mark-ridden test subjects flooding into the corridor, Sakura immediately began weaving hand signs— Snake, Ram, Boar, Horse, Bird— and clapped, green wisps of chaotic energy curling from her palms as she slowly drew her hands apart.
"Wind Style: Gale Palms!"
It was then that Sakura noticed something off about the corridor, as her wind chakra-infused palms somewhat let her read the air currents. There was wind slipping through the gaps in the wall behind her, which could only mean one thing: there was empty space beyond it— one that was at least connected to the outside!
Feeling her splayed fingers pressing against the very air, Sakura snapped her palms towards the wall, releasing a shockwave that brought it down in a shower of bricks. From the wetness of the mortar, Sakura noted as she jumped through the hole, the tunnel had only recently been sealed off.
"Oh no, you don't!" snarled Guren. "Crystal Style: Crystal Wheel!"
Guren cartwheeled, casting a ring of solid crystal as she spun, and landed neatly on the inner side of the still-spinning arc. Now enclosed within a monowheel of her own making, she urged it faster, the sharp, blade-like ring carving into the stone-tiled floor and slicing through her own men like a hot knife through butter as she gave chase to Sakura.
Sakura snapped her hands out, and the air before her shimmered— but Guren sliced straight through the crumbling wall and the oncoming pressure wave, forcing Sakura to leap to the ceiling and cling there to avoid being bisected as Guren shot past her below, her crystal wheel screeching to a halt as she turned to face her.
"Crystal Style: Growing Crystal Thorns!"
As beautiful and as deadly as a rose, Guren's chakra solidified into twining crystal brambles that rapidly filled the already narrow tunnel, forcing Sakura to twist and contort herself as she ran along the ceiling, dodging the jagged thorns jutting from the coiling vines.
"Chidori!"
As the spiky brambles closed off her path, Sakura had no choice but to wreathe her hand in lightning and carve a way through, biting her lower lip as thorns snagged onto her clothes, tearing her red dress and slicing open wide gashes across her skin as she dived through the rapidly shrinking gap.
Sakura burst through the wall of thorns, bloodied and raw. She tucked in her head and limbs, rolled on landing, and sprang forward at once, hitting the ground running. The end of the tunnel was in sight— if she could just reach open space, she'd be able to use her techniques to their full potential!
But before she could even get close to the end, a wall of stench hit her, a noxious odour so potent it made her open wounds burn. The condemned tunnel opened into a vast underground coliseum with rows of jail cells instead of spectator boxes and stands. It smelled like something had died… and as Sakura soon discovered at the tunnel's end, she'd been off by well over a hundred.
In the coliseum's arena, hundreds of corpses lay in varying states of putrefaction. Clearly, Orochimaru's captive test subjects had been made to fight one another to the death, and no one had bothered to clear away the remains— figuring it simpler to block off the entire wing of the hideout and hope the stench didn't seep through.
Hearing the slow, deliberate sound of footsteps behind her, Sakura whirled around. If she were captured, she could only imagine that her fate as Orochimaru's favourite plaything would be far worse than that of the dead men rotting in the arena before her…
"Ugh, it reeks in here," said Guren in disgust, pinching her nose as she emerged from the tunnel, the crystal brambles twisting out of her way to let her past. "Honestly, you couldn't have picked a worst place to fight. You should have just stayed in my Crystal Prison— because I'm going to make you pay for getting this stink on my clothes."
"You shouldn't have left Kabuto behind," said Sakura, cracking her knuckles. "Now, I've got you all to myself, and I won't stop until I've sucked you off— I mean, sucked you dry."
Sakura's black tomoe spun.
On closer inspection, three six-sided Jade Crystal Mirrors orbited Guren. Completely transparent, they allowed her to see through them, yet they made it impossible for Sakura to plunge Guren directly into a Genjutsu by blocking direct eye contact!
Guren had clearly done her homework— if Sakura attempted a Sharingan Genjutsu: Saimingan, her hypnotic chakra would just bounce back in her face. She needed to get rid of those mirrors, somehow… but how?
…
The Three-Tails' Appearance Arc had been the very last one Sakura ever watched, thoroughly convinced that filler was a waste of time after enduring a gruelling— and frankly excessive— 23 episodes: the equivalent of two full modern anime cours filled with almost nothing at all!
But that being said, Sakura had watched all of it in her past life, so she vaguely remembered the details. At least, better than she remembered some of the original series' more boring filler.
…
Among netizens, it was commonly thought that crystal chakra was in part composed of earth chakra, which would explain how Kakashi's Chidori could so easily shatter Guren's techniques when all else could barely put a dent in her hardened crystals, as everyone knows earth is weak to lightning— but Sakura wasn't so certain this was the case.
In nature, electricity has nothing to do with crystallisation.
Water freezes into ice crystals when the temperature drops, and salts and silica crystallise when they supersaturate, causing them to stick together in very specific, repeating patterns around a nucleus— a crystal's seed, so to speak.
However!
As Sakura had discovered earlier, electricity is inextricably linked to a crystal's very nature. Strike a piezoelectric crystal, and it generates surface charges— apply an electric field to the same crystal, and it returns the energy in the form of vibrations. Rub two crystals together, and they make light.
That being said…
If a static, unchanging electric field is applied to the nucleation site of a young, budding crystal… the crystal's growth accelerates dramatically, and the resulting formation is of significantly higher quality, as the vector field guides its development!
As the crystals Guren produces are cool to the touch, one can assume the following three chakra natures are involved in Crystal Style, making it a Kekkei Tōta:
Earth Style: the crystals' building blocks.
Water Style: to smoothly transport the earth nature chakra clumps into place, before drying off.
Lightning Style: to force the earth nature chakra into proper alignment, making crystals rather than rocks.
As the Pokémon type chart teaches us, a dual-type Pokémon will take neutral damage from an attack that is both super effective and not very effective against it— therefore, Lightning Style cannot be Crystal Style's weakness.
"Which means," Sakura muttered to herself, "Crystal Style's weak point is actually…"
The reason Kakashi's Lightning Style: Chidori is specifically so effective against Guren's Crystal Style is because… the alternating current it generates forces her crystals to sporadically vibrate at their resonant frequency, triggering catastrophic failure in their ordered structure!
"High frequency sounds!"
(Which is why Rinji's bats and their ultrasounds could also interfere with her crystal generation!)