Insight and Alchemy Setup
The hot spring stank of spoiled water, steam rising lazily from the poisoned pools as the party tried to stay on the edges where it was slightly cooler. Megumin groaned, holding her stomach. "I knew relaxing from a waterfall spa without checking it first was a bad idea." Aqua, already pale, nodded miserably. "And you said this was supposed to be relaxing before he showed up!"
Darkness pinched the bridge of her nose. "I don't even want to know what that slime is doing to the water chemistry." Kazuma groaned, leaning against a rock. "Yeah, yeah. We're all miserable, but look at him." His eyes darted to Ruko, who was calmly kneeling by the water's edge, inspecting a small vial with a flicker of intensity in his gaze that made the others pause.
Ruko didn't glance up. His hands moved smoothly, mixing powders and liquids with precision he hadn't shown in months. "If the water chemistry is destabilized, Hans will adjust to maintain cohesion. I need to force a reaction were he can't predict," he muttered quietly. His voice was calm, almost casual, but the subtle strain in his eyes betrayed the mental load he was carrying.
His Insight had activated, quietly analyzing every ripple in the poisoned pool, every minute shift in the slime's form, predicting how it would react to interference. The party had never seen him work like this. Even Kazuma, who had survived more disasters than he cared to count, couldn't hide his unease. "What is he doing? Is he trying to cook something in the water?" Kazuma muttered under his breath.
Aqua floated closer, eyebrows furrowed. "Don't touch the water, without me! You could make it worse." Ruko ignored them, continuing to measure, pour, and mix with a steady rhythm. "I've already calculated the reaction rates. Your 'help' would just get in the way," he said without looking up. Megumin groaned again. "Are we going to blow up like last time?" Darkness, surprisingly calm, observed quietly. "It's… precise. There's logic to this. I think it might actually work but I'm not sure what."
Ruko's Insight guided his hands. Every adjustment he made accounted for the current water flow, the composition of the slime, and the effect of ambient temperature. He mixed a second batch with tiny, almost imperceptible changes in the reagents, his eyes narrowing slightly. "This one will create a minor catalyst bubble.
It should destabilize Hans' cohesion for long enough that Aqua can channel Purify safely," he explained, voice still casual, but the party could hear the weight of concentration behind it. "Once that happens, the rest of you need to execute positions exactly as I say. No improvising."
Kazuma groaned. "You make it sound like a military operation instead of a fight with a slime." Ruko glanced at him briefly, expression calm as a cat. "Military precision avoids disasters in some way you don't. Even against slime." Aqua rolled her eyes, muttering about how he always had to be so dramatic, while Megumin tapped the handle of her staff nervously. Darkness simply nodded, understanding that this was probably the only chance they had to counter Hans without someone getting seriously hurt.
Hans, for his part, had started to shift in the water. The slime's translucent body contracted and expanded, sensing the changes in the water. Ruko's Insight picked up the subtle fluctuations in density and viscosity. He adjusted his reagents in real-time, barely blinking, his hands moving almost faster than the eye could follow.
"The slime is compensating. I need to increase the reaction's intensity by 0.2 percent. That should force it into a temporary instability," he muttered, voice calm but with an underlying edge of urgency. Every movement was deliberate; every choice calculated to maximize effect while minimizing risk to his friends.
Minutes stretched like hours. Sweat began to bead on Ruko's forehead, and his vision flickered slightly from the mental strain, but he didn't pause. His body was still recovering from Aqua's magic, and he felt the usual dull ache reminding him of his limits. Yet he pushed through. This wasn't just about defeating Hans—it was about showing the party that even in recovery, strategy and intelligence could make up for raw power.
"Alright, everyone, take your positions," Ruko said finally, standing with a calm posture that somehow still looked imposing. Kazuma moved to flank the pool, keeping an eye on potential collateral, while Aqua hovered above, preparing to channel Purify. Megumin crouched slightly, staff at the ready, and Darkness positioned herself to guard the others. Ruko walked to the edge of the pool, inspecting the mixture one last time. "Hans is stabilizing, but only barely. This is our window," he said softly, more to himself than to anyone else.
He handed a small vial to Aqua. "Channel your Purify through this. It will focus the energy where it's needed without triggering a backfire." Aqua nodded nervously, gripping the vial tightly. Megumin muttered under her breath about how this plan sounded dangerous, but Kazuma simply groaned again. Ruko crouched beside the pool, watching the slime carefully.
Insight had shown him its weaknesses, but the strain was mounting. His head throbbed, and he could feel the edges of his consciousness fraying slightly from the mental overload. "This is it," he whispered. "One coordinated strike." He gave a subtle signal with his hand. Aqua prepared her energy, Megumin tightened her grip, and Kazuma moved into position. The slime shifted again, sensing the approaching danger, but Ruko's preparations had already set the trap. His Insight ensured that every motion, every reaction, had already been accounted for—though the mental cost was already obvious.
Ruko took a deep breath, standing tall despite the strain. "Execute him now." Aqua unleashed the Purify through the vial, Megumin readied an additional magical barrier in case of unexpected shifts, and Kazuma moved to reinforce weak points around the pool. Ruko's Insight flared one last time, analyzing the exact moment of impact, predicting every possible counter.
For now, all that remained was waiting for Hans' reaction—and hoping the plan worked perfectly. Even as the first ripple of the reaction hit the water, Ruko felt the familiar dull ache of Insight draining him. His mind sharpened to a single point of focus, his body moving almost on instinct. This was the moment where strategy met action, and failure was not an option. The others trusted him, Hans didn't know what was coming, and Ruko didn't plan to let either side down.