Sei held his breath and tumbled behind a rock nearby sheltering himself.
Agrieth sneered as his aura was gradually subdued by the mysterious man, "Your Zenith burst is as powerful as ever."
Sei heard in confusion, 'Zenith Burst? What's that?' but he realized soon enough that he doesn't know everything about this world yet.
Agrieth swept his left leg backwards, bending forward. The smirk on his face was gone, replaced with narrowed eyes and greeted teeth.
Opposite to him, the mysterious man stood calmly, his hood still drawn, his cloak didn't even move even in the wind defying the laws of nature. His arm remained extended from where he had caught the lightning blade bare-handed—without even a scratch.
Agrieth spat, "You are a coward, always hiding behind that cloak and riddles."
The mysterious figure's reply was as measured as his demeanor. Lowering his outstretched hand slowly, he said coldly, "And what would you do, even if you knew?"
In that suspended heartbeat, everything changed. Agrieth lunged first, his blade slashing downward in a shower of blue sparks. Yet, the man moved like liquid shadow—pivoting with effortless grace, his coat flaring out as he delivered a precise, bone-cracking kick to Agrieth's ribs. The impact rang out, echoing through the cave like the shatter of stone.
Agrieth was hurled across the chamber, his body skidding in a chaotically with the cold floor. Hidden behind a rugged boulder, Sei watched in horrified awe, his heartbeat ringing in his ears. Each tremor from the clash of their forces made him wonder, with a mingling of terror and disbelief, whether he was witnessing the duel of monsters rather than mere men.
Agrieth didn't stay down. He rose again, blood trickling from his lips, and let out a furious growl.
"Let's stop playing."
With that he closed his eyes focusing, outstretching his arms to the side. Sei watched it with narrowed curious eyes.
Soon some threads of dark energy started to tend around his body seeping inside, his veins glowed a haunting red, and the lightning that once danced around him now pulsed ruthlessly, as if infused with a malevolent life force. His muscles tensed and bulged, his skin fracturing under the relentless strain, while his sword vibrated with fury.
"AAAAARGH!" Agrieth howled—a cry of agony laced with both pain and raw power—as the corrupt Nature Energy coursed through him like venom.
The cave seemed to quiver in fear, the very air rippling under an otherworldly pressure, and then, as if devoured by the void, he vanished. There was no explosion, no audible farewell—only a streak of blue and black lightning where he had once stood.
The mysterious man responded precisely on time, as soon as Agrieth appeared in front of him with his sword swinging down like a hammer, he stepped aside gracefully. The sword hit the ground like a bolt of thunder. The thin beams of electricity pulsed around the whole atmosphere as the stone beneath the sword shattered.
Sei ducked instinctively behind his rocky shelter, his eyes wide as fragments of debris scattered in every direction.
Without pause the mysterious man, raised both his hands. The air around him twisted and shimmered. Fierce gust of winds erupted inside the cave. The man raised into the air as a the storm incarnated within those walls.
Sei trembling behind the boulder felt the harsh slicing winds that raised the hair on his arms.
The man floated within the heart of the cyclone, his cloak still intact not even moving a little bit, he melted into the whirlwind, only to reappear silently behind the disoriented Agrieth. Before the latter could even rotate, a forceful palm struck his spine. A sudden blast of wind that launched him like a stone into the wall, shaking the cave to its very core and sending fragments of the ceiling tumbling down like brittle snowfall.
This was no ordinary control of air; it was as if the man himself had become the air.
Sei took this chance and ran towards the exit, shielding his head as shockwaves rippled across the walls and shards of stone fell down. But, The only exit he knew lay buried in a collapsed heap of stone and dust, sealing his fate inside the cave.
Agrieth stood again, defiant even in the ruin. He spat some blood and a deep grin flickering across his face, "Impressive…," he growled. His eyes burned anew as the corrupt surged back, refilling his strength. Now, his sword blazed brighter than ever—whips of ferocious lightning intertwined with that dark lightning pulsating. With a roar, he slashed sideways, releasing a searing arc of concentrated electricity, with blue and dark hue.
In response, the mysterious man raised one hand, and a circular barrier of wind spiraled into existence. The collision between lightning and tempest was like the clash of fire and water—dissolving into a fine mist of energy.
Agrieth launched himself forward again, his blade pulsing with sparks.
The man condensed and invisible sword of air in his hand, and they struck, each strike causing ripples of gust and electricity across the cave, each impact causing the ground to tremble and crack beneath their feet.
Sei glanced toward the shadowed depths of the cave where a mysterious bluish glow pulsed rhythmically, Sei realized he had little choice. With his heart pounding in terror and resolve, he ran forward trying to save himself from the chaos of the two beasts.
As Sei was running amidst the chaos, he heard Agrieth's painful cry. His face was a mix of pain and anger. Agrieth gasped for air stumbling back, the crackle in his sword dying down, "Not like this," he gritted his teeth. "How long do you think you will save him? I will surely complete my mission." he barked.
Agrieth's body was a mess, blood seeped through countless cuts, the leather jacket he once wore now torn to shreds, with a final gaze at Sei, he seethed his sword and ran towards the exit making a way through the debris.
Silence reclaimed the cave, the mysterious man still looked towards the exit, the turbulent wind gradually softened, the dust settled, and the blue light resumed its gentle, steady pulse.
Even though the exit was now open, Sei discarded his instinct to flee toward the exit. Instead, drawn by a strange mix of curiosity and necessity, he plunged deeper into the cave.
His trembling steps led him deeper into the chamber where the pulsing blue luminescence was so bright that it felt like daytime and from here the chamber split into three distinct paths— each way shimmered unbelievingly with the bluish green energy.
At these crossroads Sei realized that there was no way back, the unknown and the answers, the only way out was to press forward into the mysteries that awaited him.