How Are You So Strong?

"Yeah! Naruto-kun is burning with the flames of youth!" Rock Lee shouted.

"That's right, Lee! To keep our own flames of youth burning, we'll run a thousand laps around Konoha!" Might Guy said.

"Might Guy-sensei!"

"Lee!"

"Might Guy-sensei!"

"Lee!"

"Oh, please, cut it out, you two," Tenten said as she hurled kunai and shuriken at them.

The two continued charging at each other. Naruto's right hook struck Sasuke's jaw. Before Sasuke could counterattack, Naruto dodged and punched him in the ribs again, making Sasuke grimace in pain.

Sasuke refused to be toyed with by someone like Naruto. He would neither give up nor fall. He charged Naruto again, but the result was the same. Sasuke threw a punch, but Naruto sidestepped at the last moment and drove his elbow into Sasuke's back, knocking him off balance and sending him crashing to the ground.

"Shadow Clone Technique!" Naruto shouted, and a clone suddenly appeared. The two shadow clones stood side by side and called out their techniques at the same time.

"Wind Release: God's Whirling Torrent!" Naruto's shadow clone shouted, creating a vortex of wind before him that burst toward Sasuke.

"Fire Release: Dragon Flame Jutsu!" Naruto shouted again, releasing a stream of fire that merged with the wind vortex.

"Wind-Fire Combined Art: Sacred Blazing Flame Vortex!" they said in unison. A massive vortex of blazing flames rapidly burned toward Sasuke. Sasuke hastily dodged to the side, but his right arm was still scorched. The vortex continued drilling forward, eventually leaving a huge hole in the arena wall.

"Enough." Sasuke activated his curse mark. The instant it activated, he felt his chakra, strength, and speed surge. As black markings began spreading across his skin and nearly covered his entire body, he felt as though he could fight the whole world.

"With this power, I'll grind you into dust." Sasuke laughed madly, like a lunatic.

Naruto warned him, "I told you not to use that power. It will devour your sanity and turn you into a madman driven by nothing but rage."

Sasuke rushed forward at top speed. Just as he was about to kick Naruto, Naruto's body began to glow.

Boom.

Naruto's clone exploded, blasting Sasuke away.

But because of the curse mark, he was completely unharmed.

I should've known he'd use that variation of the Shadow Clone, Sasuke thought, angry at himself for not realizing it sooner.

"Lightning Release: Lightning Pillar!" Naruto rapidly formed hand seals. The moment he finished speaking, a dazzling light burst from his hand, plunging Sasuke's vision into darkness. Yet Sasuke remained still, his eyes fixed on Naruto.

Before long, Sasuke rapidly raised his chakra and instantly broke the genjutsu.

"Genjutsu doesn't work on me."

"It's his curse mark, Naruto," Nine-Tails interrupted Naruto's thoughts. "The curse mark makes his chakra fluctuate constantly. Only extremely powerful genjutsu can affect him." As Nine-Tails explained, Naruto nodded.

"Then let's try this."

"Genjutsu: Bringer-of-Darkness Technique!" After Naruto shouted, Sasuke's world became pitch-black. He found himself surrounded by darkness, unable to see even his own hands. Such absolute darkness was what all dōjutsu users feared most.

"Release!" Sasuke shouted, but it had no effect. Sasuke tried again, but failed once more.

Sasuke's rage flared as he used all his chakra, his curse mark glowing brightly.

On the third try, Sasuke unleashed a surge of chakra. Cracks appeared in the floor, and the genjutsu was finally broken. After releasing such an enormous amount of chakra, Sasuke was panting heavily.

"You were right, Nine-Tails. He even broke an A-rank genjutsu," Naruto said to Nine-Tails. After all, the power that snake had given him was still somewhat useful.

"I told you, genjutsu doesn't work on me." Sasuke looked at Naruto with a smug smile and swallowed a soldier pill, recovering some chakra.

Naruto raised his right arm toward the confused Sasuke.

Naruto smiled and said:

"Eight Trigrams: Vacuum Palm." Naruto gathered chakra in his arm and fired a palm of air at Sasuke.

Before Sasuke could react, he was struck in the chest.

Naruto's unexpected attack shattered Sasuke's ribs and made him cough up blood, but that did not mean he would surrender. He poured more chakra into his curse mark.

Sasuke vanished in an instant and appeared before Naruto the next moment. He kicked at Naruto's chest, but when the kick was blocked, he was surprised. Sasuke saw Naruto smiling as a blue chakra barrier formed around him.

"Rotation," Naruto said as he spun, blocking Sasuke's kick and once again sending him flying into the wall. Sasuke should have been wary after seeing Naruto use Vacuum Palm, but clearly, his arrogance was beyond saving.

"Enough!" Sasuke roared, pouring chakra into the curse mark on his body with all his might until it completely covered him.

Sasuke charged Naruto at tremendous speed. Naruto's eyes widened, and he raised his hand just in time to block a punch hurtling straight for his face.

...His speed has increased. I may need to release my Gravity Seal... or— Naruto thought as he dodged another swift kick from Sasuke.

"Chidori Stream!" Naruto shouted. Electricity surrounded his body, arcs of lightning dancing around him. The moment Naruto unleashed the Lightning Release technique, Sasuke was electrocuted and blasted backward, his body convulsing.

"How are you so strong, Naruto?" Sasuke finally realized that the guy he had once looked down on was not as weak as he had expected.

"You're not even from the Uchiha Clan," Sasuke said.

"Good thing I'm not," Naruto replied quickly.

"What?" Sasuke asked in confusion.

"I awakened my Sharingan when I was five. I'm glad I didn't join the Uchiha Clan, or I might already be dead by now."

"Then help me." Sasuke set aside his pride. He had never asked anyone for help...