A/N: MYSTERY COUNTDOWN: 2

The air was hot and humid, two words from the human world that withered in their attempts to describe the true atmosphere of one of Hell's finest beaches.

The water stretched out in a murky green as far as the eye could see. Its surface roiled and thrashed, every inch of it boiling. The beach meeting it was made of black shards of obsidian.

On that rocky stretch were two demons. They sat in lovely beach chairs beneath a blood-red umbrella with stand and spokes of bone. The buildings of a beachside resort rested in the distance.

"Nice day…" The one with the head of a catfish spoke. A sunhat shielded some of their delicate whiskers.

Their companion nodded. "At least people are still coming," he said as best he could around the tusks jutting from his mouth. Aside from his teeth, he resembled a nurse shark with the legs of a human. A beanie was on his head.

The first demon fell silent.

"Gestaal?" said the nurse shark demon. They frowned. "I see you're still worried."

Gestaal's two pairs of eyes flitted around as if they were checking for bystanders. "Of…of course I am. You know what's been happening…"

They sighed. The stump of a tail from their cat-like body twitched. "If the rumors spread any more than they have already, Kotokoto Beachside might just be done for."

"Don't say that," their companion said. "Don't even think it!"

The catfish demon smiled. "I appreciate your concern, Marxl."

Marxl shook his rounded head. "Just trying to be supportive."

Then his voice dropped to a hush. "But, well…they are true rumors after all, aren't they? About the monster…"

Gestaal's whiskers quivered. "Apparently so…" Their top row of eyes drifted over to the boiling ocean.

"How many have died now?"

"The last one washed up on shore just two days ago," said Gestaal. One furred hand reached out for their drink. "It was the same as all the others—bloated, peeling, and horribly mangled." They shuddered.

Marxl made a face. "The time passing between each attack is getting smaller. Our beast must be getting hungrier…or angrier, I suppose. I wonder who will be next." He grinned. "Maybe it'll even come out of the water soon."

"Don't scare me like that!" Gestaal begged.

"I'm just saying." Marxl shrugged. "You should be careful."

"But it's strange…" said Gestaal. "I've hired so many monster hunters and they've all been sent out on the sea. They've placed traps, brought weapons…but they haven't found anything yet. They say that the sea is too deep and murky."

Marxl nodded solemnly. "I see."

"The only thing that's gotten any reaction so far has been bait," said Gestaal. "But even that has led to nothing but broken cages."

Marxl's brow furrowed. "I…huh. That is quite strange, I'll admit."

"Well," He raised his flipper-arms above his head in a stretch. "It's like I've told you before. Why not sell the place?"

"I told you, I don't want to."

"Come on, Gestaal." Marxl folded his hands. "I know it's not a pleasant thought. But just realize: Once you sell it, this will become someone else's problem."

Gestaal shook their head. "No, I-I can't. Not yet. I've owned this place for years. It's made me so much money…and it's a good place to be."

They looked out over the ocean's frothing surface. "There are so many demons that I've seen come and go. Even celebrities! Everyone comes for the sulfur in the water, for the rich miasma. It's believed to be a place of healing. They tell other demons, 'The boiling water is good for you…' "

Gestaal turned back to the table, a sparkle in their eyes. "Well, if you don't die of course. But that's part of the fun too, isn't it? To test your strength? And be 'blessed' if you're found worthy?"

"But they aren't dying from being boiled," said Marxl. "They're dying because your paradise is infested with seamonsters. I understand how you feel, Gestaal. But how else will you get rid of the monster?"

Gestaal sighed, their whiskers quivering. "I confess…It is a mystery…"

"Indeed," said an avianoid demon with blonde hair.

The table shifted as both Gestaal and Marxl jerked back, giving a gasp and crying out in shock respectively.

Another demon had literally poked his head into the conversation. He stood at the edge of their table, leaning in with head cocked as if to listen to important information.

"Who are you?!" Marxl exclaimed.

The new arrival paid him little attention. He tipped his head to the side, as if the data were sloshing around inside of his cranium and diluting some new solution.

He gave a short bow in Gestaal's direction. "Good afternoon. Lovely place you've got here. I've quite enjoyed the tide pools myself."

The demon then turned to Marxl. "And as for your question, I am 'Braineater' Neuro , acting crime detective. I am investigating the current happenings at this resort. Boilheart here requested assistance, I believe."

"Detective?" Marxl bared his tusks. "You can't do that without a permit."

"Where in Hell did you get that idea?" Neuro looked at him through lidded, condescending eyes. "For future reference, I can do whatever I want. And as a member of Hell's Disciplinary Action Committee I have certain…duties to the public," he bared his own sharp teeth in a grin. "So, do forgive me. But I am overriding your complaint."

"You can go to the Order Branch and look me up yourself," Neuro added lazily. He circled around the table, stopping a short distance behind Gestaal's chair and looking out at the ocean.

Marxl did not appear pacified. The demon sat rigidly in their chair, leaning over the table with clenched fists.

"Marxl-" Gestaal's voice held a warning.

"He was spying on our conversation," Marxl whispered back.

"So true," Neuro spoke again. "Do forgive me, Boilheart. I simply could not help myself once I noticed you two were discussing the case."

"I gather you're both very familiar with the details, then?" Neuro directed at the two. They nodded.

"It's horrible…" Gestaal murmured.

"Yes, horrible, horrible," said Neuro, with the air of one who has seen many more and known much worse. "But predatory worries aside…something is strange, here. It doesn't add up."

The other demons stirred. "What do you mean?" growled Marxl.

"Well," Neuro gazed out over the sea. "Let's start from the top. Demons have been going missing periodically in the waters near this resort. Witness accounts are that they go out for a swim, swim very far from shore, and eventually appear to be taken down. Sometimes they struggle. Sometimes they simply sink beneath a wave and never come back up. This has been happening for about the past year and a half."

"But their body reappears a few days later," Neuro said. "The corpse bobs to shore, as if some creature sent it on its way towards land. Some have to be fished from the water. Others wash up on the beach. All of them appear drowned. A few are missing arms, have broken necks, or bear wounds that look as if they had been in a great struggle."

Gestaal squeezed their eyes shut as Neuro went over the story. Marxl noticed their acquaintance's suffering, and was just beginning to glare at Neuro when the avianoid stopped.

"And so demons decided that only a seamonster could have done it." Neuro turned to them. "But unfortunately they are mistaken."

Gestaal's eyes snapped back open. Marxl's glare turned into a mystified stare.

"Hold on," Neuro held up a hand to cut them off. "I'm not finished."

"You see, forensic analysis turned up a strange fact. I assume you are both aware that the body goes through stages after death?"

The two demons slowly nodded.

Neuro frowned. "If so, then congratulations, you're probably lying. But anyway," he said. "What our forensics found was that the time of death did not line up with reports. Judging by rate of decomposition, rigor mortis, and body temperature, most victims had actually been dead for days before they were observed to have 'drowned'. For example, one of the bodies had been dead for a week. But he had been observed swimming out to sea and then 'drowning' just three days prior. "

"Now, how is that possible?" Neuro said. "A demon is not able to die and then come back to drown again."

There was silence as all three demons processed the information.

"Even in boiling water?" said Gestaal.

"Ahh, good catch," said Neuro. "But yes, even in boiling water."

"You see, usually what happens is that after drowning and floating for an initial day or so, a body will sink. Then a few days later, gases produced due to decomposition make it float again. The warmer the water, the quicker this process happens."

"But it's all irrelevant, really," Neuro said. "Forensic examination will still be able to determine when the body first became 'drowned'. And none of the bodies appear to have died when they were observed to."

"So you see why I doubt the guilt of a demon-kidnapping monster in this case. Besides-" A grin had found its way to the detective's face again. "Even my mind has a hard time explaining what use a seamonster would have for a storage shed."

"What shed?" Marxl gripped the table.

"Oh, there's one out back." Neuro pointed a finger off to the left. "I found it tucked behind one of the mess halls, down near the water. Big. Black. Faint horrible smell."

He grinned. "Full of dead bodies."

Marxl looked completely stunned. Gestaal nearly dropped their drink.

"D-d-dead bodies?" Gestaal said. "In my shed?"

"It's more likely than you would think," said Neuro. "And what's more…it was exceedingly difficult with some due to decomposition, but for the majority of the corpses we were able to determine their original identities."

He pointed a finger up in the air. "And every single one of them matches a demon who is currently feared taken by the monster. But, they have not shown up drowned yet. How strange."

"My theory is this," Neuro said. "Our true culprit killed their victims ahead of time. Then, they stored the body inside the black shed. Soon afterwards they themselves went out for a swim—disguised as the demon they killed. After 'drowning' themselves, all they had to do was return to the shed, drag the body out to sea, and put finishing touches on it before sending it back to land. Thus, it would look like the demon had drowned and been killed by a 'monster'. "

"Yes, boys and girls and others," Neuro's eyes flashed green. "We have a shapeshifter in our midst."

Gestaal trembled. "It can't be true…" they whispered in shock.

Marxl had gone blue in the face. "Nonsense," he blithered. "Absolute nonsense. You can't come in here and…You can't…You…"

He took a few deep breaths. "Actually, this is good. Yes. Very good. I demand that you take my good acquaintance Gestaal to see this shed immediately. I will follow behind you and go get some equipment to help-"

"So you can escape?" Neuro said. "Not a chance."

Silence fell.

Marxl turned purple. "What was that?"

"The real question is-" Neuro leaned on one shoulder of Gestaal's chair and fixed Marxl with a wicked smile. "Why are you here…if we found a body in the shed that looks just like you?"

A beat passed.

The table hit the ground with a resounding crash. Its top splintered and broke.

"ROOOOOOOOOAAAAR!" Marxl unleashed a howl that definitely could not have come from a nurse shark.

Gestaal gasped and leaned far back. Only Neuro's arm kept their chair from toppling over. "Marxl?!"

The demon's tusks began to extend. Their mouth changed shape as wide, rubbery lips took the place of soft gums. Their face became hominoid—that of an ape. Blue fur swept over their body. Their humanoid legs shifted and became heavier, stouter, and furred. The beanie stayed on their head.

Neuro felt the miasma in the air bend around them. It fueled the shapeshifter's transformation as he absorbed it from the nearby air.

But the shapeshifter appeared to be reverting to their standard form. He stood in front of them: a great blue ape with webbed fingers and toes. And his face was twisted with rage.

"Hmph," said Neuro. "A seamonkey. It all adds up now. I see that my hypothesis was correct."

The culprit answered him with another bellowed roar.

"HOW COULD YOU?" he screamed. "I was so close! Just one more day, one more week even! The fool would have sold it to me! To me!"

"I'm afraid this criminal was pretending to be your acquaintance," Neuro said to Gestaal. He stepped in front of the catfish demon, shielding them from the seamonkey's anger. "All of the murders…were actually due to him."

"I see," Gestaal said. Their eyes welled up with tears, but they held them back and kept their composure. To cry would be a damning sign of weakness. "Then…that means… the real Marxl is… Oh no. Oh no, no."

Neuro let Gestaal start to mourn as he fixed his sights on the criminal. "Your scheme ends here," he said.

The seamonkey scowled. "I'm not done yet!" He lunged at Neuro with his huge arms. "All I have to do is kill you and escape-"

Neuro swayed and dodged the attack, taking the opportunity to swiftly run up besides the other demon. The seamonkey may have been physically strong, but Neuro was quicker. And he was used to having the muscular disadvantage in fights.

"Too slow," he said.

The criminal turned to face Neuro with an incredulous look. But before he could swing again, a thought seemed to occur to him. The seamonkey reached up to feel the top of his head. His hat was gone.

Neuro twirled the beanie on one finger, digging a steady hole in it with his talon. "And there it is. The final piece of evidence." He pointed to the seamonkey's head, which was marked by a red dot and surrounding red circle, almost like a target.

"I also noticed that, among the victims, all of them swam out to sea wearing a head covering of some sort," Neuro said. "Be it a swim cap, baseball hat, or scarf, all of them were seen wearing something when they drowned. But when they washed back up, the hats were missing."

He grinned. "That really must have been you out there. That marking on your head…it stays the same during your transformations, doesn't it? You had to hide it. None of your victims had the same head marking after all, and you risked revealing your identity. Like now."

The criminal shook, one hand still patting his head as if he couldn't believe the cap was gone. "Why you…little…" they growled.

Some distance behind their fight, Gestaal stood on the obsidian beach. Their eyes flashed with anger. "End him," they said to Neuro.

"Alright monkey," Neuro addressed the criminal. "Our time here is over. I'll give you a choice since I'm so generous…"

He held up one talon. "Pain, or more pain?"

The seamonkey roared. He charged at the detective.

Neuro was unfazed. He smiled as the demon approached. "More pain it is, then."

After the excitement was over, Neuro stood on a cliff at the edge of the beach.

The criminal had been successfully subdued and taken away. It hadn't even been a fight worth mentioning, really. Gestaal had thanked Neuro profusely and gone off to cooperate with the police. There was surely a lot of paperwork and explaining to do. And there was a shed that needed cleaning up.

Neuro gazed out over the boiling ocean. The exhausted sun sank low in the sky, turning the water a beautiful slaughterhouse-red. A slight breeze blew past, carrying with it the aroma of sulfur. "What lovely weather for a beachside picnic," Neuro sighed.

The mystery had been adequate. It was enough to fill Neuro's stomach for a few wondrous moments. It had given him energy and spurred his life force, yes. But then, like so many times before, the pleasant feeling of having consumed a meal faded into nothingness.

Neuro's brow furrowed in annoyance. The quality was always so low. Demons didn't have many instincts of restraint, after all. Rampant violence was the social norm. "Crimes" were base and short-sighted and most of all…unintelligent. There weren't many demons clever enough to think beyond the obvious murder methods. Honestly, Neuro thought. Are there still demons out there who don't know that bodies decompose at a set rate?

And it wasn't like guilt, the kind that drove people to construct puzzles of the soul in order to preserve their own psyche, was something common among Hell's inhabitants.

Neuro began to grumble. "It's not enough…"

How he wished for some more intelligent demons. Not ones like himself (Devil, no) but just ones who thought beyond the usual. Ones who would go to any length to avoid detection. Ones that treated crime like the riddle it was.

There must be a better mystery out there. Neuro's fist tightened at the thought. He had to keep going. There had to be something that could actually satisfy him for more than thirty seconds. Briefly, Neuro wondered if all the mysteries of Hell would ever be enough-

A disturbance in the water caught his attention.

The bubbling surface calmed in the shape of a circle near the cliff's edge. As Neuro watched, the waters became still, eventually stopping completely. Then, a giant neck emerged from the waves.

It shot up, up, and up, eventually coming to rest just a few feet above Neuro. A head was at the top of it. Two huge eyes, yellow with black pupils and ridged by small teeth, peered down at him. A pair of nostrils flared.

Neuro was looking at a seamonster.

The detective watched it calmly. "It has been over 50 hours since I arrived," he said. "You had to come up for air eventually, I see."

The monster made a low groaning noise. Every inch of its body was a greenish-blue, the exact color of the boiling sea. A second mouth opened and closed in a vertical oval between its eyes. Ribbed horns curled up from the monster's head and its ears flared out to the side like a goat's. Fangs poked over its lips from both the top and bottom, resulting in a appearance like stitches. The faint splashing of flippered appendages came to Neuro from below the cliff.

"I see," Neuro said. "You are a 'Kisshi', right? From the same family as the infamous Loch Ness Monster. They still tell stories of you in the human world."

"To think there was a monster in the boiling sea after all…" He shook his head. "Well, no matter. I'm sure you were not responsible for those murders. Only the broken cages and taken bait."

He spread his arms out wide. "I have a proposition for you. Lately, I've been wanting something animal-based to add to my arsenal. You just might be worthy of the job."

"What do you say?" He gave it a knife-blade grin. "Join me?"

The seamonster rumbled. It reared back a few paces and fixed Neuro with a stare. They held eye contact for a minute, emerald with onyx. Then, the monster stiffened.

It gave a cry, backpaddled, and turned to flee.

Immediately, Neuro held up a hand. A light shot out from the front of his talons. "Sorry," said Neuro. "I am refusing your refusal."

Out on the ocean, a break in the sky appeared. It took the form of a square demonic apparatus with a short tailpiece extending down from under it. It had a blue border and a purple middle, looking almost like a book. Eyes embedded in the top twitched back and forth. The device split down the middle as its two sections opened up like shutters.

The monster fled right into it. The doors closed behind the beast as it let out a screech of indignation.

777 Tools of the Demon World—Evil Window, Neuro thought as the new Tool adjusted and then stabilized. He dismissed it from sight.

Perfect. Neuro was pleased with the new development. He recalled something about being able to create new Tools to use himself. Neuro would just have to notify those who granted him the 777 Tools of the Demon World in the first place. Then he would have to follow some other minor procedures in order to register a new Tool. There were plenty of useless ones that Neuro was willing to replace.

And it seemed the caged beast would be guaranteed to be angry whenever Neuro chose to unleash it.

Neuro grinned. "I always wanted a pet," he lied.

Afterword: Evil Window was an anime-only Tool that appeared in episode 15.

Fun facts about this episode:
-Apparently "x? In my y? It's more likely than you think" (ie: "Dead bodies? In my shed?") is a meme. I honestly had no idea. But it fits too perfectly for me to take it out, I think. XD
-Kotokoto is the Japanese onomatopoeia for "boiling water", so that's where the name of the beach comes from.