Jin adopted a stance that resonated with the dominance of the water element, silently preparing for the impending confrontation.

Kigai, observing Jin's poised stance, couldn't help but chuckle. 

"Ah, the water deserter," he sneered. 

"You're Jin, the hero who once saved the small village of Shu from a giant demon attack. No wonder you have the courage to face me."

Jin's eyes narrowed at the mention of his past, the weight of his previous exploits woven into the fabric of his current quest. 

Jin, unfazed by his past being brought to light, smiled resolutely. 

"Who cares about the past? I'm here now, and I'm proud of my decision."

Kigai, with a sinister smile, responded, 

"Is that so? Then let's see who is stronger."

The clash began, Jin unsheathing a water sword, attacking with the precision of a samurai. Kigai evaded gracefully, moving in a circular dance, demonstrating an uncanny agility. To Jin's surprise, Kigai conjured a water sword of his own, engaging in a fierce clash.

As the battle intensified, Jin questioned, 

"Are you a water user?"

Kigai laughed and, with a sudden twist, created a fire bomb that exploded in Jin's face. Reacting swiftly, Jin shielded himself with a water barrier, leaving him puzzled by the unexpected turn of events.

Kigai then pulled whips made of vines, floating in the air. Jin, astonished, asked, 

"What the hell is this?"

In a dramatic display, Kigai combined all four elements into his whips. 

"I am a master of all four. Only three people can use all four: my father, the Supreme Commander, Mamoru, and myself."

Jin, piecing together the puzzle, realized the connection between Mamoru and the Mana Vanguard but couldn't fathom why.

"Are you Mamoru's..." 

Jin began to ask, but Kigai interrupted with a cold confirmation, 

"Yes, he is my brother," 

his voice tinged with disgust. The revelation left Jin grappling with the complexities of the unfolding battle and the intertwined fates of those he once considered allies.

As Jin grappled with the revelation of Mamoru's connection to Kigai, he couldn't help but ask, 

"But how is that possible? Is he a demon?"

Kigai, shrouded in silence, offered no further explanation. Instead, he launched a relentless attack on Jin, showcasing the mastery of his combined elemental powers.

Jin defended with his water sword, but Kigai's movements were a dance of fluidity and precision. With a swift flick of his hand, Kigai summoned tendrils of earth that ensnared Jin's legs, restricting his mobility. The air around Kigai crackled with a poison that struck Jin, disrupting his focus.

Seizing the opportunity, Kigai formed a swirling vortex of fire, sending it hurtling toward Jin. Despite Jin's efforts to create a water barrier, the intense heat weakened his defense. Kigai, ever agile, exploited the opening and struck Jin with a rapid succession of blows.

Jin, battered and disoriented, struggled to regain control. Kigai, unfazed, continued his assault, weaving in and out of different elemental attacks. The Forbidden Cave echoed with the clash of powers, each strike amplifying the ominous aura enveloping the battlefield.

As the battle unfolded, Jin faced the harsh reality of Kigai's overwhelming mastery over the elements. The air crackled with tension, and the fate of Shinpi hung in the balance as the clash between water and the fused elemental forces raged on.

As Makoto entered the chamber, her eyes widened in horror at the sight of Jin on his knees, bloodied and battered. 

"Jin!" she screamed, her voice echoing through the cavern.

Kigai, displeased by Makoto's entrance, sneered, "What are you doing, flame brain?"

In a sudden twist, the leader of the Flaming Dojo emerged from the shadows, seizing Makoto and turning her into a hostage. The cavern fell silent, tension thick in the air as Kigai's sadistic grin spread across his face.

"Can't wait to see Mamoru's face as his dear friends perish," 

Kigai taunted, relishing the cruel anticipation. Makoto, now caught in the clutches of the Flaming Dojo leader, exchanged a worried glance with Jin, a silent plea for a plan to escape the impending doom that hung over the Forbidden Cave. The stage was set for a dire confrontation with Mamoru, whose fate intertwined with the lives of his cherished comrades.