Elemental Hero in Teyvat

Diluc: Anyway, there is something I want to clear up with you brat.

Sekai: What is it, old man?

He asks as Diluc summoned his sword and pointed towards Sekai.

Diluc: Lets finish our fight…

Everyone was shocked except for Sekai who anticipate this from someone who wield great sword. He just looks at Diluc with blank expression and sigh.

-Small TimeSkip-

Right now, the group is currently outside of the Traven. The groups and few people was watching intently toward Sekai dan Diluc making a standoff.

Diluc: Now then shall we continue what we left at the temple?

Sekai: *sigh* let just finish this. Sekai Solar Power!

He said this as he summons Solar Sword pointing towards Diluc.

Wasting no time Diluc attack with flame embedded wave strike from his claymore. Seeing this, Sekai evades it using Solar Leap.

Then, he points pistol gesture and start barraging red-haired old man with mini–light Beam. Using his speed, the red-haired swordman dodge Sekai's assault.

Diluc: (I see, this might take a while)

Diluc thought while continue dodging towards area with less people to gain a safe distance from Sekai.

But Sekai suddenly uses Solar Leap out of nowhere towards Diluc and punch him to the face, knocking him off balance but Diluc manage to recover quickly. Sekai rushed forward to engage Diluc, Diluc block several of Sekai's strike but he continues pressuring him. Diluc could block but found it hard to push Sekai away from him.

Diluc manage to make a comeback by deflecting Sekai slash and kick Sekai away from him. Diluc then send powerful flame embedded heavy strike at Sekai.

Sekai uses Solar Leap to move backward dodging Diluc preemptive strike, but Diluc continue making strike forward and chain it with powerful overslash that knock back Sekai away from him for a few distance. Attempting to rob Sekai chance for any recover, Diluc rush forward to strike again.

The silver adventure found that while he could defend and deflect Diluc strike, he could not defend from fire-based attacks, he can change to cyclone elements, but it hurt his swordman pride. If he actually has any, afterall he starts the fight with gunning down Diluc from afar with light beam. 

Using Solar Leap to back away, he starts concentrating solar energy in front the sword points and aimed it towards Diluc.

Sekai: Eat this!! Solar Beam Strike!

Diluc's eyes widen in shock as Sekai releases his attack, but he manages to react quickly, instantly put his sword to use as a shield, and still get knocked back from the blast.

Diluc manages to recover from Sekai's attack, he gets up from the ground.

Diluc: *pant* Not bad, this *pant* is getting interesting…

Sekai: Oh yeah *pant*, think you can *pant* keep up?

Diluc: How about we take the heat to the next degree?

He said as his sword began to ignite in flames. As Sekai put Solar Sword once more and pointed towards Diluc.

Sekai: Don't be bitching on me when you have back pain tomorrow old man.

Diluc: Oh yeah, well see about that brat!!

Both Sekai and Diluc charged at each other at full speed, their blades meeting in a furious clash. Sparks erupted with every strike, the sharp clang of metal ringing through the streets of Mondstadt. Each blow sent ripples of force through the air, their movements a proof of both swordman skill.

Meanwhile, a crowd had gathered, drawn by the intense duel. Among them, Eula arrived and noticed the Acting Grandmaster standing alongside the bard and the Traveler, all watching the fight unfold.

Her gaze shifted toward the center of the commotion, where Sekai and Diluc exchanged relentless blows. The raw intensity of their battle caught her interest, a flicker of intrigue sparking in her eyes.

Back to fight, both Sekai and Diluc continue to exchange blow after blow both refuses to back down.

Diluc lunged at Sekai, his claymore cutting through the air with force—only to slash at empty space. In the blink of an eye, Sekai had vanished.

Before Diluc could react, a blur of light appeared behind him. Sekai, using Solar Leap, reappeared mid-air, his sword already in motion. With a swift but powerful strike, he slammed the back of sword hilt against Diluc's side.

Frowning, Diluc charge back at Sekai only for him to block the strike, parry it and slash Diluc, but he manages to dodge it.

Sekai starts by charging towards Diluc to attack up close, but the red-haired swordman vanish and attack Sekai from behind. Acting on instinct, Sekai turns and block Diluc strike with Solar Sword and then back flips while releasing Solar Blade Wave from distance.

Diluc then counter with flaming projectile at the incoming Solar Blade Wave, as the two attack collide it create huge explosion causing a strong gust of wind around the area for brief moment.

Sekai instantly began slashing again sending another Solar Blade Wave, Diluc began twirling his body and jumping to avoid incoming blade wave. Sekai continued his assault on the red-haired swordman until he manages to corner Diluc, launching himself straight to Diluc but he manages to fend him off by kicking him away a few distance making Sekai backflip to regain his composure.

Diluc: Then how about we end this for good.

Sekai tensed as he sensed the shift in energy. Diluc's claymore began to glow, embers dancing around its blade as waves of heat rolled off it. The Pyro element surged, coiling around the greatsword like a living flame, growing more intense with each passing second.

The pressure in the air grew heavier. Sekai could feel the sheer force radiating from Diluc's weapon—an attack fueled by raw power.

Diluc: Time for-retribution! Phoenix Flame!!

With a fierce shout, Diluc swung his claymore, unleashing a devastating slash. A massive phoenix of roaring flames erupted from the blade, its wings spreading wide as it charged toward Sekai with blistering speed. The sheer heat distorted the air, making the battlefield feel like a furnace.

Sekai narrowed his eyes. In a flash, he propelled himself backward with Solar Leap, his figure vanishing momentarily before reappearing a short distance away. His stance shifted, one hand resting on the hilt of his sword as his body stilled, energy condensing around him.

The spectators held their breath.

Sekai: "Zantetsuken."

A single, precise slash. But in reality, it was multiple slash too fast that it looks like a single clean slash. 

A gleam of silver cut through the inferno. The moment Sekai's blade met the flaming phoenix, the fiery beast froze—then, in an instant, split apart. The flames shattered into countless embers, scattering harmlessly into the wind, leaving only a trail of light flickering in the night sky.

Diluc's eyes widened in disbelief. The crowd erupted in gasps and murmurs, struggling to comprehend what had just happened. 

Diluc: "W-What…?"

A sharp sound rang from above. Diluc's instincts flared as he snapped his gaze upward—Sekai was airborne, his sword glowing like a miniature sun. Flames of pure solar energy coiled around the blade's edge, condensing into a crescent-shaped arc of golden light.

Sekai: "Time to sleep, old man! Solar Blade Wave!!"

With a powerful slash, Sekai unleashed a massive wave of scorching light, cutting through the air like a celestial judgment. The golden arc expanded as it descended, carving a fiery path toward Diluc.

Diluc gritted his teeth and tried to brace himself, but the force of the attack was overwhelming. The moment the wave struck the ground beside him, a radiant explosion erupted, shaking the battlefield with its sheer intensity.

As the light faded, the crowd stood frozen in shock. Sekai landed gracefully, his sword lowered but still humming with residual energy. Diluc, still standing for a brief moment, let out a shaky breath before his claymore slipped from his fingers. His knees gave out, and he collapsed onto the ground.

Sekai exhaled, his Solar Form dissipating as his jacket returned to black. He sheathed his sword, wiping a bead of sweat from his brow before giving a nervous smile as he looked at Diluc.

Sekai: You will pay for the damage right old man… hehe…

Then suddenly Sekai passed out due to exhaustion as he dropped to ground as well.