As the light from the crystal enveloped them, Kai felt a sudden and overwhelming wave of exhaustion wash over him. His vision blurred, the vibrant hues of the Abyssal Heart fading into a soft, muted gray. The new power, the **Zenith Reflex**, had pushed him far beyond his limits. He tried to steady himself, to focus on his breathing, but the strength in his legs gave way, and he stumbled.
Reina noticed immediately, her eyes widening. "Kai!" she shouted, rushing forward to catch him before he hit the ground.
Kai's breathing was ragged, his skin pale, beads of sweat dotting his forehead. "I… I'm okay," he mumbled, though his voice was weak, strained.
Yuta knelt beside him, concern etched across his face. "Kai, you've overdone it," he said softly, placing a hand on his brother's shoulder. "That power you used—it took a lot out of you."
Kai tried to nod, but his head felt heavy, his eyelids fluttering. "Just… need a second," he whispered, but the words were barely audible.
Kaito, who had remained at a distance, stepped forward, his brow furrowed. "He's burning out," he said. "The **Zenith Reflex** is not something just anyone can handle. It's a power that taps into the deepest reserves of energy and will. If you push too far… you pay the price."
Reina shot him a glare. "And you didn't think to mention that before?" she snapped. "Kai could've killed himself!"
Kaito's expression remained calm, but there was a flicker of regret in his eyes. "I didn't expect him to awaken it so soon," he replied. "It usually takes years to reach that level of mastery. But Kai… he's different."
Arion, still riding the high of their victory, frowned. "Different or not, we need to get him back. Now." His voice was urgent, but there was an undertone of worry that hadn't been there before.
Kai's breathing grew shallower, his body trembling slightly. "Reina… Yuta… I… I can't…" His voice was faint, almost lost in the void around them.
Yuta tightened his grip on Kai's shoulder, his face tense. "Stay with us, Kai. Don't give in now. We've come too far for you to back out like this."
Reina nodded, her voice firm despite the fear in her eyes. "Yuta's right. Kai, you're stronger than this. You've always been strong enough for all of us."
Kai tried to focus on their voices, tried to ground himself in the here and now, but everything felt so distant. His consciousness wavered, darkness creeping at the edges of his vision. "I… can't…" he muttered again, the words slurred. And then, the world around him went black.
---
When Kai awoke, the first thing he felt was a dull ache coursing through his entire body. It was as if every muscle, every bone had been stretched to its breaking point and then left to throb with a deep, pulsing pain. He tried to move, but a soft hand gently pushed him back.
"Don't move," Reina's voice came, soft but commanding. He blinked, his vision slowly coming into focus, and he saw her sitting beside him. The room was dimly lit, and he could make out the familiar shapes of the academy's infirmary.
Kai groaned, attempting to sit up again. "What… what happened?"
Reina's face was a mixture of relief and frustration. "You passed out," she said, her tone half-scolding. "After using that power. You were out for hours."
Kai closed his eyes, trying to remember. The battle with the Guardian, the surge of energy, the feeling of time slowing—then nothing. "I… I couldn't control it," he admitted, a hint of frustration in his voice. "It was like… everything was moving so fast, but I was moving faster. And then… I hit a wall."
Yuta leaned against the wall nearby, his arms crossed. "You hit more than a wall, Kai," he said, a hint of a smile breaking through his serious expression. "You hit your limit. And then some. You're lucky you didn't tear yourself apart."
Kai let out a small, tired laugh. "Always pushing too far, huh?"
Reina sighed, shaking her head. "You have no idea. But seriously, Kai, you scared us. That new power, the **Zenith Reflex**, it's… incredible, but it's dangerous."
Kai nodded, wincing slightly as he tried to sit up again. "I felt it. Like it was tearing me apart from the inside out." He paused, looking between Reina and Yuta. "But we won, right?"
Yuta's smile widened. "Yeah, we won. Thanks to you. The Guardian is gone, and we have the crystal. But you need to be careful with that new ability."
Kaito's voice cut through the room as he stepped forward from the shadows, his expression unreadable. "He's right, Kai. The **Zenith Reflex** isn't something to be used lightly. It's a double-edged sword. It draws from your very essence, your soul. Too much, and you might not wake up next time."
Kai's eyes narrowed at Kaito. "Why didn't you tell me? Why keep that a secret?"
Kaito met his gaze without flinching. "Because I didn't know you'd reach that level so quickly. The **Zenith Reflex** is rare, even among the most skilled warriors. You managed to tap into it without training, without preparation. It was unexpected, to say the least."
Reina, her eyes still focused on Kai, interjected. "It doesn't matter now. What matters is that Kai is okay, and we have what we came for. But we need to think ahead. If this was just a taste of what's coming…"
Yuta nodded, his expression turning serious again. "Then we need to be more prepared than ever. This isn't the end; it's just the beginning."
Kai, still lying down, closed his eyes for a moment, letting their words sink in. "So… what's next?" he asked quietly.
Arion, who had been standing at the doorway, arms crossed, finally spoke up. "What's next is we rest, regroup, and figure out our next move. Whatever's out there, we need to be ready for it."
Kaito nodded in agreement. "And Kai… you need to learn to control that power. Properly this time. Because we'll need every ounce of strength you have if we're going to face what's coming."
Kai smiled faintly, his strength slowly returning. "I'll do my best," he said, a hint of determination in his voice. "I promise."
Reina squeezed his hand gently, her face softening. "Just don't push yourself too hard, okay? We need you… in one piece."
Kai chuckled weakly. "I'll try… no promises."
The room fell into a comfortable silence, each of them lost in their thoughts, the reality of their situation settling in. The challenges ahead would be even greater, the stakes higher. But they were together, and that gave them strength.
Kai took a deep breath, feeling the weight of their words and the bond they shared. Whatever came next, he knew he wouldn't face it alone.
To be continued...