The Poison Beneath the Steam
Steam rolled endlessly across the hot spring, thick enough to blur the wooden beams and stone edges into soft shapes. What should have been a place of rest felt wrong—too quiet, too heavy. The water itself looked clear, but the smell was off. Not rotten. Not sharp. Just… wrong.
Ruko sat on a flat rock near the edge, towel over his shoulders, boots off but still dressed. He hadn't entered the water. His instincts refused to let him. Around him, Axis followers groaned, coughed, or leaned weakly against the railings. Some were already laid out on mats, faces pale and sweaty.
"This is bad," Kazuma said, crouching beside him. "Like, really bad. I knew this place was cursed. But I didn't knew it to this extent." Aqua stood knee-deep in the spring, hands glowing faintly as she tried purification magic again. "It doesn't make sense!" she snapped.
"This is sacred water! It's connected to my homeland! It shouldn't be able to make people sick!" Megumin sat wrapped in a towel nearby, face flushed, clearly uncomfortable. "I don't feel good," she muttered. "My stomach hurts. And my mana feels… heavy."
Darkness nodded stiffly. "Several people collapsed after soaking for only a few minutes. This type isn't normal exhaustion." Ruko watched quietly. He counted symptoms. Weakness. Nausea. Mana disruption. Delayed reaction. His fingers tapped lightly against his knee.
"Ruko," Kazuma said, lowering his voice. "You've been staring at the water like it owes you money." "It does," Ruko replied calmly. "It's seems is under thw current." Kazuma blinked. "The water?" "Yes and no you stupid." Aqua turned sharply. "What do you mean beneath?"
Ruko stood, ignoring the dull ache still lingering in his body. "If this was natural contamination, the effects would be uneven. Some people would be worse. Some better. But everyone who entered the spring is affected the same way." "So?" Kazuma asked.
"So someone made sure of that." The Axis priest nearby looked offended even while sweating heavily. "A-Are you suggesting sabotage?! This is holy ground!" "Holy ground gets targeted first," Ruko said flatly. Aqua clenched her fists. "Who would do this—but you said it was the demon general?!"
Ruko didn't answer immediately. Instead, he crouched and dipped two fingers into the spring—just barely. The moment he pulled them out, his expression sharpened. "There's something mixed into it, even though it was the demon general " he said. "Not enough to change the color. Enough to bind with mana."
Megumin's eyes narrowed. "Poison?" "We already discussed that. But something close," Ruko replied. "And it also a bit smarter." Kazuma groaned. "Please don't say slime." Ruko start to get angry. "We already said that ago. What is up with your head for once."
A low gurgle echoed from deeper within the spring. Everyone froze. The water near the center began to ripple—not from movement, but pressure. Like something breathing underneath. Bubbles rose. Slow. Thick. "Oh no," Kazuma whispered. "Nope. I hate this arc already and im not ready for this."
The surface broke. A translucent mass rose slowly, its shape unstable, body shimmering with oily colors beneath the steam. Its surface pulsed, mana reacting violently with the water around it. The smell worsened instantly. Several Axis followers screamed.
The slime lifted higher, forming a crude face—two depressions for eyes, a stretched curve that passed for a mouth. "Ahhh…" it said, voice wet and amused. "So many believers. So much faith. You really do make the best soup." Aqua stepped back, furious. "YOU—!"
The slime laughed. "Yes, yes. You may call me Hans." Kazuma pointed at it, shaking. "WHY is it always slimes?!" Hans oozed forward slightly, the water around him darkening. "Relax. I'm not here to kill you all. Not yet. Just… weaken you. Pollute the source. Let belief rot slowly."
Ruko moved without hesitation, stepping between Hans and the sick civilians. "You picked the wrong place, you ugly sack a goo," Ruko said. Calm. Direct. Hans tilted. "Oh? And who are you supposed to be?" "Someone who doesn't like people poisoning water," Ruko replied. "It's quite lazy actually and i was about to take a hot soak."
Hans chuckled. "Strong words for someone still injured." Ruko's eyes narrowed slightly. For a moment, something clicked in his mind—not a vision, not a prophecy, but patterns lining up too cleanly. The timing. The symptoms. The way Hans spoke.
This wasn't a random attack. This was preparation. Ruko exhaled slowly.
"Kazuma," he said quietly. "Get Aqua away from the spring. Her magic is feeding him." "What—HEY!" Aqua protested as Kazuma grabbed her arm. "Let go!" "JUST TRUST HIM FOR ONCE!" Kazuma yelled, dragging her back.
The moment Aqua stepped away, Hans hissed. "Tch. Sharp." Megumin struggled to stand. "Ruko… if I cast Explosion—" "You'll collapse and be done for," Ruko said instantly. "And he'll survive, so don't consider it." Hans grinned wider. "He's right." Darkness clenched her fists. "Then what do we do?"
Ruko scanned the area. Buckets. Pipes feeding the spring. Stone channels leading toward the waterfall upstream. "Well we don't fight him here," Ruko said. "This place is his advantage." Hans laughed. "Running already?" "No," Ruko replied. "Just isolating the problem that needs to be flushed."
He turned to Kazuma. "This slime didn't just poison the spring. He's poisoning the source and i already state that already." Kazuma swallowed. "The waterfall…" "Yes." Hans's body pulsed violently. "Oh," he said pleasantly. "You're smarter than you look." Ruko felt the pressure in his head increase. Not pain. Just… strain. Like holding too many thoughts at once.
He ignored it. "We cut off his control of the water," Ruko continued. "Then we deal with him." Aqua stared at him. "You're giving orders like a leader now." "I'm giving instructions," Ruko replied. "And i dont know what I'm doing. Big difference."
Hans began sinking back into the spring. "Enjoy your little investigation. I'll be waiting upstream." The slime vanished beneath the surface, leaving the water darker than before. Silence followed. Kazuma exhaled shakily. "Okay. That's a Demon General. Right? Please tell me that's a Demon General."
"Yes he is you stupid, what else could have," Ruko said. "And he's patient as well. Hmph, cocky bastard." Megumin hugged her towel tighter. "Now I'm starting to hate patient enemies." Ruko looked toward the distant sound of rushing water beyond the trees.
His body still hurt. His think of a solution. But his skills were rusty. His alchemy untouched for too long. But his mind was already moving. "Everyone who drank the water needs to stop," he said. "Now. We move upstream. Slowly. And carefully." This wasn't over. It had just started.