When the Serial Killer Next Door Gained Harem System

Ken looked like he was about to fall asleep in the middle of the arena. He sat with his legs stretched out, holding the shortsword loosely, his eyes half-lidded as he stared at nothing.

I kept swinging the dagger.

My grip was tight, fingers wrapped firmly around the handle, thumb pressed along the side for control. I raised it just above shoulder level and brought it down in a straight, controlled motion, then lifted it back up along the same path. The movement had to stay consistent, same speed, same angle, no slowing down.

"Maan..." Ken exhaled, dragging the word. "Aren’t you bored?"

"I am," I said, breathing a little heavier, but not stopping. "But it’s training." 𝑓𝓇𝘦ℯ𝘸𝘦𝑏𝓃𝑜𝘷ℯ𝑙.𝑐𝑜𝓂

The system only counted one swing per second. If I slowed down or hesitated, the timer would reset. So I kept the rhythm steady, even as the burn in my arm got worse. My shoulder started to tighten, my forearm felt heavy, but I forced each swing to match the last one.

"Last ten seconds..." I muttered, focusing on the motion. "Come on..."

I kept going, lifting and dropping the dagger with the same pace, even as my arm trembled slightly near the end. When the timer finally ended and the small UI popped up next to my vision, I let the dagger drop to my side and fell onto my back, breathing hard.

I stayed like that for a moment, then checked my status.

╔═══════════════════════╗

> Ace | LC: 62 | EXP: 183/236 | LVL 4

╠═══════════════════════╣

> HP ▰▰▰▰▰▰▰▰▰▰ 110/110

> MP ▰▰▰▰▰▰▰▰▰▰ 70/70

> STA ▰▰▰▰▰▱▱▱▱▱ 45/90

────────────────────────

> Class: MAGE

> Known Abilities:

• Fireball

• Heal

────────────────────────

> PERKS

• +10% More magic damage

• +10% CRIT chance

• Backstab DMG

╠═══════════════════════╣

> [ BAG ] [ MAP ] [ SHOP ] [QUESTS]

╚═══════════════════════╝

I was agonizingly close to leveling up. While I stayed on the ground for a moment to catch my breath, I pulled up the quest log to see if there was anything I could knock out quickly. Surprisingly, I found exactly what I needed to push me over the edge... and it wasn’t even listed in the quests menu. It was a world quest icon shimmering on the map, located just a short distance from the boys’ dormitory.

It was a "Race" challenge. The objective was simple: reach the marked location, wait for the countdown, and then sprint through a series of checkpoints. The rewards, Gold, Silver, or Bronze, depended entirely on my performance. If I could snag the Gold, the XP would be more than enough to finally hit my next level.

"Worth a try..." I muttered.

"Heey..." Ken said, still sounding half-dead. "Let’s practice, man. You aren’t scared or anything, right?"

"Hey, I’m F," I replied, pushing myself up. "And you’re C. Of course I’m scared."

"Come on, man. Please? We’ll use wooden swords! Please, please, please! I’m soooo bored."

"Fine," I said. "But no spells."

"Oh, yeah!" He got up immediately, all that boredom gone. "Let’s do it."

"So what’s the rules?"

"This arena is protected," he said. "Stick your dagger into the ground and wait."

I crouched and pushed the dagger straight into the dirt. After a few seconds, the metal began to change. The shine faded, the edge thickened, and it turned into wood. I pulled it back out and tested the weight. Lighter, dull, but still balanced.

Ken did the same with his shortsword, waited for it to change, then pulled it out and gave it a small swing.

A golden energy formed around the edge of the arena and rose up, curving inward until it covered the entire area like a dome.

"What’s this?" I asked.

"It activates automatically," Ken said, taking a few steps back. "So spells don’t hit anyone outside. It’s a barrier."

I walked to the edge and pressed my hand against it. It felt solid.

"Alright," Ken said, turning toward me. "Ready?"

We stood a few meters apart. I raised the wooden dagger to head level, blade angled slightly inward, elbow close to my body. My stance tightened, weight balanced between both feet, ready to move forward.

Ken took a wider stance, one foot in front of the other, knees slightly bent. He held his shortsword diagonally across his body, tip aimed toward me, ready to react.

"Let’s start," he said.

I moved first.

I pushed off my back foot and closed the distance, keeping my upper body slightly lowered and the dagger close to my head. My steps were quick but controlled, not rushing blindly.

Right before reaching him, I dropped my weight and slid forward, extending my leg in a low sweep aimed at his knee.

He reacted fast. He pulled his leg back and stepped out of range, then immediately swung his sword upward, aiming at where my torso would have been.

I stopped my slide by planting my foot hard into the ground, pulled my leg back, and twisted my body to the side. Using that momentum, I threw myself into a roll, my shoulder hitting the ground first before I pushed myself back up.

I stood again, resetting my stance, dagger raised.

Ken smirked. "Cheap move."

I brushed some dirt off my sleeve. "It would’ve worked."

"Now let me show you how it’s done."

I adjusted my grip slightly and lowered my center of gravity, ready this time to react instead of rushing in.

"By all any means, Ken."

Ken shifted his weight forward, boots scraping lightly against the arena floor. His shoulders tightened, grip firm on the shortsword. For a split second he stayed still, then he burst forward, closing the distance fast. When he stepped into range, his hips turned and he swung horizontally at my midsection, aiming to catch me before I could react.

I was already watching his shoulders. The moment they moved, I raised my dagger. Instead of meeting his blade head-on, I angled mine diagonally, catching the flat of his sword and redirecting it downward. The impact slid along my dagger with a sharp wooden crack, and I pushed just enough to guide his strike off its path without fighting his full strength.

His sword dipped toward the ground, leaving his balance slightly forward.

I pivoted on my front foot, turning my body sideways to him. My left hand dropped for balance as I lowered myself, then I snapped my leg out in a low arc and kicked at his left ankle. The hit connected cleanly. His stance broke, and his weight gave out under him.

Ken hit the ground with a thud, air rushing out of his lungs.

I stepped in immediately, planting my foot against his chest to keep him down, dagger held loosely but ready in my right hand. He looked up at me, exhaling, then lifted one hand in surrender.

"Fine, fine. You win," he muttered. "But why did we fight without casting any spells?"

The golden barrier around the arena faded, the light dissolving into the air. At the same time, the wooden coating over our weapons peeled away in faint particles, revealing metal underneath again.

I lowered my foot and reached a hand down to him. He grabbed it, and I pulled him back up.

"Like I said," I answered, brushing dust off my tunic. "You’re C. I’m F. I’m not taking that fight with spells involved."

"Eh," he shrugged, sheathing his shortsword. "Fair enough."