Naruto: I am Nara Shikamaru

"Ninja Art: Sand Coffin."

As Gaara finished speaking, three sand spheres surrounding him abruptly burst with a muffled thud. Blood spattered from within, the scent of iron heavy in the air. Three genin from the Hidden Stone Village were killed on the spot.

"Come out."

Still immersed in his bloodthirsty state, Gaara suddenly turned toward the nearby forest, his hoarse voice carrying like a blade in the wind.

"Heh… as expected of Gaara of the Sand. Impressive, really impressive."

A voice rang out from behind a tree, Shikamaru's voice. He stepped into view, appearing before Gaara and his teammates.

"A Konoha ninja?" Temari narrowed her eyes at the sight of the headband on Shikamaru's arm.

"Hmph. What's a brat from the Leaf doing here?" Kankuro sneered coldly.

"Hmph. You two, stand down."

Unexpectedly, Gaara snapped at Temari and Kankuro, brushing past them with cold disinterest. His blood-red gaze locked onto Shikamaru, gleaming with killing intent. "You're strong. What's your name?"

"Nara Shikamaru." Shikamaru answered with a slight smile. He could tell Gaara was still in his twisted phase, using bloodshed as proof of his existence. It wouldn't be until Naruto defeated him that Gaara would begin to change.

"Heh…" Gaara licked his lips, a disturbing habit that sent chills down even Temari and Kankuro's spines. "Nara Shikamaru, if I kill you, I'll prove my worth even more."

"Ninja Art: Sand Coffin!"

As he raised his hand, a wave of sand surged toward Shikamaru like a tidal beast.

"Tch." Shikamaru smirked dismissively, his body suddenly blurring before vanishing entirely, leaving only an afterimage in his place.

So fast! All three of the Sand siblings' pupils contracted. Even Temari and Kankuro couldn't track his movement.

"Shadow Style: Shadow Fist!"

Boom! 

Shikamaru's figure flashed before Gaara, his right fist cloaked in shadow chakra slamming into Gaara's sand shield with a fierce gust.

Shadow Fist, Shikamaru's original jutsu, created during his time training outside the village. A seal-less C-rank ninjutsu infused with his unique shadow chakra.

But that wasn't all. Shikamaru had developed an entire set of original shadow techniques using his Yin-aligned chakra, his own "Shadow Style" ninjutsu.

Boom! 

Gaara's sand shield shattered under the force of the blow, and Shikamaru closed in.

"Ninja Art: Shadow Imitation Technique!"

His hands moved in a flash, completing the hand signs in less than a second. Dark shadows shot out from beneath his feet, racing toward Gaara.

"Sand Shield!"

Sensing the threat, Gaara quickly raised a wall of sand, barely blocking the Shadow Imitation in time.

"Damn, just as I thought. Techniques that require hand signs are too much trouble…"

Shikamaru clicked his tongue in frustration. If it weren't for that one second delay, he was confident he could've taken Gaara down instantly.

Whoosh! 

Gaara countered with a wave of sand, but Shikamaru immediately activated a substitution jutsu, vanishing and leaving a log to take the hit. The sand swallowed it whole.

Then, Shikamaru's voice came from directly behind Gaara.

"Shadow Style: Shadow Rasengan!"

Right hand raised, Shikamaru stood behind Gaara, a spiraling orb of pure black chakra forming in his palm. A technique inspired by Naruto's Rasengan, it was currently Shikamaru's most powerful original jutsu.

"Ah!" Temari screamed, shocked at the power radiating from the attack, and turned to see Gaara's grim expression.

Sensing the lethal chakra behind him, Gaara's gourd disintegrated into sand, forming a shield to block the incoming Rasengan.

"You think that'll stop my Shadow Rasengan?"

A sneer flashed across Shikamaru's face. Gaara was exactly the type to stand still and rely solely on defense, perfect for target practice.

Boom! 

The sand shield resisted for a moment but was quickly pierced. With a loud crash, the Rasengan slammed into Gaara's back, sending him flying. The sand at Shikamaru's feet lost its chakra and scattered to the ground.

"Gaara!"

Temari and Kankuro cried out, rushing to shield him as he hit the ground hard. Gaara slowly rose, his sand armor cracking and falling away in chunks, revealing his true form. He stared at Shikamaru, trembling, his face a mixture of hatred and fear, unable to move.

"Ahhh!"

Suddenly, Gaara clutched his head and screamed, muttering in a broken voice, "Why… Why…"

He was on the verge of losing control.

"Gaara, calm down!" Temari cried anxiously, fearful he would lose it and unleash Shukaku, the One-Tail.

"Heh… enough playing around. I'll be taking this 'Earth Scroll.' See you at the tower."

Shikamaru shrugged, uninterested in fighting an unstable Gaara. He knew Gaara was far from his full strength in this state. Better to wait until after Naruto defeats him.

He casually picked up the Earth Scroll from the dead Iwa genin and vanished in a flash, leaving behind a stunned Temari, Kankuro, and a trembling Gaara…

⚔──────────────

Note: About the Shadow Rasengan… well, he invented it because, come on, if you transmigrate into the Naruto world, you might as well start inventing jutsu left and right, right?

It's similar to Menma's Rasengan from the Road to Ninja movie