I Accidentally Built a Harem of Girls Who All Hate Each Other

Time, as they say, is relative. For a physicist, it's a dimension. For a student in a boring lecture, it's a thick, unmoving sludge. For me, standing in that alleyway under the full, undivided attention of Reina Kujou's furious crimson gaze, it had ceased to exist entirely. My past, present, and future all converged into a single, horrifying point of pure, sphincter-clenching panic.

My life wasn't just flashing before my eyes; it was being meticulously reviewed, audited, and prepared for liquidation by the Kujou Corporation's newly-formed "Department of Kaito Tanaka's Unfortunate Demise."

Reina Kujou rose to her feet with a fluid grace that defied the fact she had just been sprawled on the grimy pavement. She brushed a non-existent speck of dust from her perfect skirt, her movements stiff and jerky, like a wind-up doll that had been wound too tight. The cat, the furry orange instrument of my doom, chose this exact moment to abandon her and trot over to me, rubbing its flank against my leg with a rumbling purr.

I could feel Reina's glare intensify, burning a hole straight through my soul.

"Don't. Touch. It," she hissed, her voice a low, dangerous whisper that was infinitely more terrifying than a shout.

"R-right," I stammered, holding my hands up in a gesture of surrender. I gently nudged the cat away with my foot. "Sorry. I didn't mean to... uh... witness."

'Witness? What am I, a character in a bad crime drama? Smooth, Kaito. Real smooth.'

"You saw nothing," she stated, her chin lifting in a weak attempt to reclaim her authority. It was like watching a queen try to command an army after her castle had just crumbled around her.

"Absolutely," I agreed, nodding vigorously. "Saw nothing at all. I was just... admiring the structural integrity of this brick wall. It's very... brick-like."

A vein pulsed in her temple. "Do you take me for a fool, Tanaka-kun?"

"No! Of course not, Kujou-san!" I said, my voice cracking. This was it. The end. I was going to be buried under the new gymnasium. "Look, I'm sorry I laughed. It was involuntary. I promise, your secret is safe with me. I won't tell a soul. Cross my heart and hope to… well, you know."

I made a vague crisscross motion over my chest. Reina watched the gesture, her eyes narrowing. She took a step closer, invading my personal space. I could smell the faint, expensive scent of her perfume, a mix of lavender and pure, unadulterated intimidation.

"A promise from a commoner like you holds no value," she said, though a flicker of something unreadable—was it surprise? confusion?—passed through her eyes. She had expected me to grovel, to bargain, to try and use this against her. The idea that I would just… let it go… was clearly not in her playbook.

"My word is all I have," I said, meeting her gaze with as much sincerity as I could muster. "And I give it to you. I won't say anything."

She stared at me for a long, silent moment, her crimson eyes searching mine for any hint of deceit. The alley was silent save for our breathing and the distant purr of the traitor cat. The furious blush on her cheeks had subsided, replaced by a cold, calculating mask. She was processing. Re-evaluating.

The first bell for class shrieked through the morning air, shattering the tense bubble around us. I jumped, my shoulders hunching up to my ears.

"I... I have to get to class," I said, taking a tentative step backward.

"You are not dismissed," she snapped, her voice regaining its usual icy command. She had found her footing. "Your 'word' is insufficient collateral. I cannot risk a secret of this magnitude on the fickle whims of a simpleton."

'Simpleton? A little harsh, but probably fair given my current brain function,' I thought.

"To ensure your… discretion," she continued, choosing her words carefully, "I will need to keep you under my direct supervision. From now on, you will report to the Student Council office immediately after your final class. Every day. Until I am satisfied that you are no longer a threat."

My jaw dropped. "Every day? But... I haven't done anything!"

"You've done everything!" she retorted, her composure cracking for a second. "You saw. That is your crime. This is your sentence. Do you understand?"

It wasn't a question. It was a royal decree. Before I could formulate a protest that wouldn't result in my immediate expulsion, she turned on her heel and strode out of the alley, her back ramrod straight, the very picture of the Ice Queen once more.

I was left standing there, my mind reeling. I had just been sentenced to indefinite after-school detention for the crime of accidental observation.

I stumbled into homeroom a full two minutes after the bell. All eyes turned to me. Ms. Fujii, our homeroom teacher, gave me a look of gentle concern from her desk.

"Tanaka-kun, are you alright? It's not like you to be late," she said, her warm voice a soothing balm on my frayed nerves.

"Sorry, sensei. I was... detained," I mumbled, bowing apologetically.

I scurried to my seat, acutely aware of the stare drilling into the side of my head. It came from Yui. Her expression was a carefully neutral mask, but her eyes were asking a thousand questions, and none of them were pleasant. I gave her a weak, apologetic smile, which she did not return.

My heart sank. Level one of the trouble-pocalypse had been initiated.

And then, the classroom door slid open again.

In walked Reina Kujou.

A collective gasp swept the room. Reina Kujou was never late. Ever. She probably arrived at school before the janitors.

She offered a curt, formal apology to Ms. Fujii, her face an unreadable porcelain mask. But as she walked to her seat in the front row, her crimson eyes met mine for a fraction of a second. It was a look that said, 'This is your fault. Remember our deal.'

The whispers started instantly. They were quiet, but I could feel them, like a change in air pressure.

"...Tanaka and Kujou-sama?"

"They both came in late..."

"No way, him?"

I sank lower in my chair, wishing the floor would swallow me whole. I risked a glance at the other students. Asuka Miyamoto was looking back and forth between me and Reina with a curious, almost amused glint in her fiery eyes. Shiori Akiyama, in her corner, had her book held up a little higher than usual, her knuckles white. She had seen me help her, and now she saw this. The math wasn't adding up in her favor.

But the most terrifying reaction was Yui's.

She wasn't looking at me anymore. She was staring straight ahead at the blackboard, a serene, placid smile on her face. It was the kind of smile a predator might have while patiently waiting for its prey to make one wrong move. The air around my desk felt like it had dropped twenty degrees.

The rest of the day passed in a blur of anxiety. Every rustle of paper, every cough, felt like a judgment. Lunch was a tense affair where Yui's questions about my morning were a masterclass in polite interrogation. I fumbled through excuses about helping a teacher, but I could tell she didn't believe a word of it.

Finally, the last bell rang, signaling the end of classes and the beginning of my prison sentence.

I packed my bag with the speed of a man on death row. My only hope was to get to the Student Council room before Reina could summon me over the school-wide intercom system, an act that would surely elevate my social status from "non-entity" to "target for public execution."

"Ready to go, Kai?"

Yui's voice was right beside me, sweet as cherry blossoms, but carrying the weight of a guillotine. She stood there, her own bag slung over her shoulder, smiling that terrifyingly calm smile.

This was the moment of truth.

I swallowed, my throat suddenly dry. "Actually, Yui... I, uh... I can't walk home today."

Her smile didn't falter, but it became brittle, like a thin sheet of ice. "Oh? Why not? Do you have club activities I don't know about?"

"No, it's... I have to go to the Student Council office," I said, the words feeling like poison on my tongue.

The effect was instantaneous and devastating.

The smile on her face didn't just fade; it shattered. The warmth in her eyes vanished, replaced by a deep, cold void. Her hand, which had been resting on her bag strap, clenched into a tight, white-knuckled fist. The friendly girl-next-door disappeared, and in her place was someone I barely recognized, someone whose aura screamed betrayal.

"The Student Council... office?" she repeated, her voice dangerously soft. "With her?"

I didn't need to ask who "her" was.

I looked from Yui's icy glare towards the front of the classroom, where Reina was already waiting by the door, tapping her foot impatiently. She gave me a sharp, commanding look.

I was trapped. Caught between the immovable object of an Ice Queen's blackmail and the unstoppable force of a childhood friend's jealousy.

My peaceful, invisible high school life was officially over. I wasn't just on the radar anymore. I was at ground zero of a war I had accidentally started, and I had a sinking feeling that the casualties were going to be catastrophic. Starting with me.