Taming my Monster Girl Harem from Scratch

After that, Yu Na led us back to her training center.

I thought we'd be going to one of the rooms, but she brought us deep underground instead. It took us about ten minutes just to walk down the stairs, spiraling downward. When we reached the landing, the space before us made everyone gasp in awe.

"That's... big."

"It's like a skyscraper fitted inside the underground!"

"Fatima, what's a skyscraper?"

"A skyscraper is a tall building, mocking gods by reaching for the heavens above."

As the girls were chatting, Yu Na walked to the side of the building before opening something that looked like a chute.

"You can drop the essence crystals for the fuel here. It should be consumed automatically as soon as you enter and close the door."

As she explained, she moved to the dial beside the door. There, a series of numbers were shown, from 0 up to a thousand. Yu Na changed the value from the 10 it had before to the 100 that I asked for.

"With this, time should run 100 times faster inside than outside. However, be careful if you're planning to spar inside since destroying the barriers would lead to the parabolic time accelerator failing."

Yu Na kept explaining things to me, while Ember kept note of it. There were a lot of precautions, probably because the entire room was not only expensive, but it was also hard to repair. After all, the time-element monster that helped create it was no more.

"..."

Anyway, it's time we enter. Checking the time, it was about 3 hours before midnight. If everything went according to our schedule, then we should be out by 9 a.m. tomorrow.

"Everyone, ready?"

I turned behind me, checking everyone's faces. All of them nodded simultaneously, making me smile at their synchronous action.

"Then, let's go!"

I entered the room first, opening the sealed door with a bank vault-like wheel with a five-hand spindle handle. It was hard and heavy to turn, giving me an idea of just how tough the mechanism inside it was. As soon as I pushed it open, everyone entered.

"It's narrower than I thought...!"

The outside proportions didn't match the inside at all, meaning there must be tons of mechanisms placed around the entire room. It was wide, though, roughly half a kilometer long on each side. A cubed, pure white room.

*SLAM!*

After everyone entered, the door closed behind us. The large spindle began spinning, gaining speed, until it snapped into place, stopping abruptly with a loud bang.

*HUMMM!*

And then, the low hum of the mechanisms echoed shortly before fading. I looked around, but nothing seemed to have changed.

"Is the time acceleration already on?"

I can't tell if it was active or not. Thankfully, Ember was there to the rescue.

"Master, my connection to the satellite is still maintained, and the feed from it was showing an almost still image. The time acceleration is active."

With her confirmation, I firmly nodded my head before turning to everyone.

"Listen, right now, I'll be passing you one god-level essence crystal each. Your task is to absorb its energy until the limit by suppressing your own evolution process."

Usually, one would evolve immediately upon reaching the required level. However, that would mean there's not much excess energy going into the feedback. This plan relies on maximizing the energy we can gain from it, so we can't stop midway.

"It will be hard and painful, but I believe in you all. Fina, Judy, Yorm, there's no need to push yourselves, alright? You're only at the 5th stage, so if you can't handle it anymore, proceed with evolution."

The three nodded firmly, staring at the essence crystal in my hand.

"Fatima..."

"There's no need to warn me. Who do you think I am?"

As a former god tamer, I guess it would be easy for her to manage her excess energy. Finally, I turned to Igni, who was the closest to reaching the 9th stage among everyone.

"Igni, take your time. We don't want to cause complications in your evolution just because of this little stunt."

The barrier between the 8th and 9th stages wasn't limited to the energy level. There's also talent, skills, fate, and many other small factors.

But once a monster under a tamer breaks through to the 9th stage, then the other monsters under him will have an easier time breaking through. The experience of each monster could be shared with their tamers, and vice versa, after all.

"I will, My Lord. Please don't worry. I won't let you down."

I checked on everyone once more.

Ember, Fang, Minerva, and Hekate. The four were practically in the middle of the scale, where they would neither have difficulty breaking through nor have trouble controlling their energy.

Everyone was ready, so I quickly began my own preparation. I took out a large table and placed food on top of it before using a refrigeration artifact in the middle of it.

"I'll be placing the food and water here, so just help yourself when you need it."

When we begin, I won't be able to move until everyone finishes. I have no choice but to fast while meditating, waiting for the energy backflow during their evolution.

After setting everything up, I moved to the middle of the room and sat down cross-legged. There, the girls surrounded me at even intervals, in the order of them getting contracted. Ember was in the 12 o'clock position, and the rest followed clockwise.

"Phew..."

I took a deep breath before whispering to my mental scape.

'Primo, Brother Mountain, I'll leave the rest to you two in case something happens.'

Of course, I wouldn't trust myself completely just like that. I'm not perfect, after all, and I could still end up making mistakes. I need to prepare in case everything goes south. The two of them, hearing my monologue, quickly sent a positive response.

With all preparations done, I finally gave the signal to the girls.

"Alright, let's start!"

Twelve hours in the real world. A total of 50 days inside this time accelerated room. Our mass rank-up journey begins!