When the Serial Killer Next Door Gained Harem System

We had to wait nearly ten minutes before it was finally our turn to enter the arena. Two teams had been using it before us, five students against one in what looked more like a public beating than actual training. By the time they finished and left through the side gate, the sandy floor of the arena was full of footprints and snapped practice arrows.

The three of us walked inside together.

The arena felt even larger from the inside, with rows of seats climbing upward for spectators during tournaments and official matches, though it was way, way smaller than what we had at the academy. A few students from other classes lingered around outside the arena fence, watching out of boredom before heading back toward their dormitories.

Mio stepped forward first.

The night wind pushed against her short red hair as she turned toward us and crossed her arms. Thin lines ran across her cheek and near her jaw, old marks that had healed years ago. Combined with the way she carried herself, she honestly looked more like a veteran mercenary than a student.

Meanwhile, I was standing there trying not to think about how badly this whole tournament idea could go wrong.

"Alright," Mio said. "Let’s figure out what we’re working with."

Ken rested his hands behind his head casually while I stayed quiet.

"I’m a Ranger," Mio continued. "And so is..."

"Ken," he replied quickly, pointing at himself with a grin.

"So is Ken," she finished. "That gives us two ranged fighters already."

Her eyes moved toward me.

"Ace. Which class are you actually going to use?"

"That’s the problem," I admitted. "I still don’t know."

Ken snorted. "He woke up blessed by every class and still can’t decide."

"I’m serious." I rubbed the back of my neck. "What if I mix classes?"

Mio blinked once.

Ken lowered his hands.

"You mean switching between them?" Mio asked.

"No." I shook my head. "Actually merging them. Like Warrior and Cleric together or something."

Silence settled over the arena for a second. Even the wind suddenly felt louder.

Ken frowned and looked down at the ground, thinking hard. "Wait... I remember reading about something like that."

"Are you sure or..."

"No, seriously." Ken snapped his fingers. "There was some famous guy a long time ago. He merged Warrior and Mage."

"A Spellblade," Mio finished quietly. "That was his class, he found out after testing it. But he wasn’t from this kingdom."

"That’s the one."

She looked back at me immediately.

"You can’t just do that, Ace. Hybrid classes are ridiculously rare."

"Well..." I muttered. "Maybe I can."

I focused on the system menu.

The translucent interface appeared silently in front of me, hidden from everyone else’s sight. I navigated toward the new skill I had unlocked earlier. As soon as I selected it, another smaller menu opened above the main one.

Two empty slots appeared. For the first slot, I selected Warrior. For the second, Mage.

The system paused for a brief second before another prompt appeared, asking if I wanted to merge both classes.

I confirmed it.

╔═════════════════╗

> CLASS MERGE

╠═════════════════╣

> WARRIOR + MAGE

───────────────────

> RESULT: SPELLBLADE

╚═════════════════╝

"Let’s pretend I can do it," I said casually, hiding the system again. "Would it actually help us?"

Ken stared at me like I’d grown a second head.

"Help us?" he repeated. "Ace, Spellblades have their own abilities."

Mio nodded slowly. "Unique ones."

"Not just unique," Ken added excitedly. "Rare. Like, ridiculously rare. Even S-class students can’t use those skills unless they naturally awaken that hybrid class."

"Oh."

That was... actually useful information.

I immediately reopened my status screen out of curiosity.

╔═══════════════════════╗

> Ace | LC: 156 | EXP: 156/490 | LVL 6

╠═══════════════════════╣

> HP ▰▰▰▰▰▰▰▰▰▰ 115/115

> MP ▰▰▰▰▰▰▰▰▰▰ 85/85

> STA ▰▰▰▰▰▰▱▱▱▱ 68/100

────────────────────────

> Class: SPELLBLADE

Known Abilities:

• Blazing Cleave

• Battle Renewal

• Arcane Bulwark

────────────────────────

> PERKS

• +15% Magic Damage

• +10% Critical Chance

• Backstab Damage

• Light of the Believer

╠═══════════════════════╣

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

╚═══════════════════════╝

So my skills really had changed.

Useful.

The last thing I wanted was to accidentally reveal another ridiculous ability in front of everyone during the tournament. My entire plan was still to fake an injury somehow and quietly remove myself from the competition before things became complicated.

No flashy powers. No attention. No becoming the center of another rumor.

I closed the system window before either of them noticed me zoning out again. "Good to know," I said. "Anyway, what were you saying before?"

Mio narrowed her eyes slightly like she knew I was hiding something, but thankfully didn’t press further.

"Right now," she said, "we’ve got two Rangers and whatever you decide to become."

"Let’s just say Mage for now."

"Two Rangers and a Mage," she repeated. "That’s not exactly ideal."

Ken sighed dramatically. "We need a frontliner. Somebody to actually take hits."

"We can still work with this," Mio said calmly. "The tournament isn’t only about brute force. Coordination matters too."

She uncrossed her arms and pointed toward the center of the arena floor.

"We’ll start simple. Two versus one."

"Sounds fair," I replied.

"Ken and I will team together first," she continued. "You’ll fight us alone, Ace."

"Wait, seriously?"

"You need to learn pressure quickly."

Ken grinned. "Don’t worry. We won’t kill you."

"That is incredibly reassuring."

Mio ignored us both and continued speaking.

"No real arrows. No lethal spells. No headshots. We’re testing reactions, movement, and teamwork."

"We already prepared for that," Ken said proudly as he grabbed the quiver hanging at his waist. "Wooden-tipped arrows."

"Oh." I nodded. "That’s actually smart."

"Of course it is." He smirked. "Unlike you, some of us came prepared."

Mio walked backward toward the opposite side of the arena floor and rolled her shoulders loosely.

"Take your position, Ace." She said, "Ken, you act like a Rogue."

"Got it."

I stepped forward into the middle of the sandy arena, feeling every bit as underqualified as I probably looked.

Ken moved to the right side while Mio drifted left, both naturally spreading out to surround me from different angles. Just from that alone, I could already tell they had more experience than I did.

Mio reached behind her shoulder and smoothly pulled her bow free.

Ken copied her a second later.

Both aimed directly at me.

"Ready?" Mio asked.

I swallowed once and slowly nodded.

"Not even slightly."

I switched my class back to Mage and let out a slow breath. So class merging could really be done instantly, even during combat. That was honestly broken. If I learned how to use it properly, I could probably adapt to almost any situation on the fly.

For now, though, I only had three basic mage spells.

Not exactly impressive.

"On one," Mio said while stepping backward across the arena sand. "Three. Two..."

I raised my hand toward her instinctively, heat already gathering in my palm. A faint orange glow flickered between my fingers as Fireball prepared itself. My stomach tightened slightly.

This was just practice. No real danger.

Still stressful, though.

Turns out getting shot at with arrows, even wooden ones, triggered something very primal in the human brain.

"One!"