Remote Vigilante

 Sebastian swings his sword in the air to clean it of monster blood. He is about to sheathe them when he notices visible cracks on the black blade.

"Ah, shit."

 He only then remembered that he might have pushed the blades' capacity to store and channel void energy past their limit in his previous fight with Crowe's monster, even going above the prescribed limit once.

 He sheathes them back carefully and decides not to use it any further as to not worsen the damage it has already sustained.

"I'll just stop by Kristoff tomorrow," he thought.

"Next," he tells mission control through his earpiece. In front of him are several corpses of small, humanoid, gray-skinned creatures. A B-ranked endeavor at the foot of some mountain range that he finished in less than 20 seconds.

"S-sir, that's the eighth mission in the past half hour," the personnel points out, a hint of worry in his voice.

 Feeling miserable, Sebastian goes on a mission spree hoping to take his mind off of what happened with him and Rina. And this time, he's not hand-picking missions. He's taking everything that's available regardless of rank.

"What time is it over there?" he asks.

"Um, it's a little over 10 in the evening, sir."

"Huh. Ten 'o clock, eighth in the past 30 minutes. Well, I'm doing this shit until you see the sun outside, buddy," he tells mission control.

"Now give me the next one."

"Y-yes, sir! There's uh… we have detected an A-rank horde, sir."

"A-rank, finally," he comments.

"I'm getting bored of these fodders."

 In the eight missions he has completed so far, only three of them were measly B-ranks. The rest were C-ranks that he could have done in his sleep.

"We have confirmed their location, si—"

 His accomplice suddenly stops talking, as if something interrupted him.

"It-it's back," his accomplice mumbles.

"What is it?" he asks.

"It's… gone, sir," even his accomplice seemed dumbfounded.

"What do you mean 'gone'?"

"T-the horde's signature, sir," the man answers.

"They're disappearing one after the other."

"Maybe you're just not looking right and someone was already sent in there," Sebastian queries.

"That's not possible, sir. We detected this only around five to 10 minutes ago," the man shoots down his theory.

"Someone, something is out there exterminating monsters again."

"'Again'?" he asks.

"This has happened before?"

"Only occasionally, sir. And it's usually just around this vicinity," the man answers.

"And it's not one of ours?"

"Yes, sir."

"And none of you has ever seen whatever this thing is? I mean, any clue or anything? Satellite visual?"

"We have nothing, sir."

"Talk about having the best tech in the world," he grumbles, mockingly.

"I'll check it out, where is it?"

"We're confirming the coordinates, sir."

"Is it still there?"

"We don't know, sir. But the horde is already exterminated."

"We've confirmed the coordinates, sir."

"Alright, hit me."

SHHOOM

 He warps in the middle of a forest, just a couple of meters away from some beaten path leading to some place he has no clue of. He doesn't even know where he is and it's daytime.

"Holy shit, it's broad daylight in this place," he comments.

"Where is this?" he asks his now, trusted partner.

"It's an isolated volcanic island south of Tokyo, sir."

 He looks around, trying to locate the scene of the crime which can't be far off.

 Hidden behind some clearing are four dismembered corpses of large, lizard-like monsters with dark gray, charred skin. Body parts lying everywhere on the grass, even the dismembered parts had several stabs and cut wounds. Whoever did this did not hold back at all. He approaches the murder scene to get a closer observation.

"Is there no signature from whoever did this?" he asks while traversing the forest brimming with tall grass and plants.

"None, sir."

"Hmm. No signature, so this isn't a monster with friendly-fire activated," Sebastian's observation.

"We have a vigilante on our hands."

"Are you a hundred percent sure this isn't one of ours?" he asks again, just for confirmation.

"A hundred and ten, sir. If this was an agent, you'd have seen them by now."

"Yeah, you're right."

"You mentioned this only happens around this vicinity?" he asks, looking at the maimed corpses filled with cuts and stab wounds.

"Yes, sir."

"And this is a remote island?"

"That is correct, sir."

"That means our guy is just here somewhere," he notes, squatting down on the corpses to get a much closer look.

"Is this place populated?"

"The island's population is less than 200, sir. The main village is not far from where you are."

"And accessibility for outsiders?"

"Not good, sir. Only possible modes of transport are either a ferry or a helicopter."

"Bingo," he says, getting up.

"Our vigilante is a villager here."

"You guys never thought of sweeping this place to look for him? How long has this been happening?" he adds.

"I, I don't know, sir… I've only been here for three months," his accomplice answers.

"We report it to Sir Alois everytime it appears but we're given no other orders about it so we haven't really had the chance to dig into it," the man adds.

"Yeah, higher-ups probably don't care about it. It's unpaid help as far as they're concerned," Sebastian points out.

"Anyway, you need to send some people here ASAP, it's broad daylight and there's a mass grave here. And this isn't really that hidden from sight."

"We're on it, sir."

"I'm not in the mood for a witch hunt," Sebastian could have tried looking for the culprit himself but decides to put it on the to-do list for the meantime.

"Now, give me the next one."