Harem in a dungeon from another world

Larisa leads me back to her office, and I fill out the paperwork. Which amounts to a receipt for Aya. 
"Now naturally, she'll be given a binding crest that will make her obey, as well as other effects." She says. "But we also have skilled artisans that can tattoo or brand her if you like. For extra cost, of course."
I thought about it for a moment. "I want to feel her out first. Can one be added later if I change my mind?"
"Of course."
I nod. "Then, for now, just the crest."
With the paperwork done, I counted out the silver—650 pieces. That left 350 of my original budget. But only 150 off my estimated budget... not bad at all.
Soon, there was a knock at the door.
"Enter," Larisa ordered.
The elf slave entered again, this time escorting Aya on a leash. Her hands had been bound behind her. Larisa stood and took a marker-like object out. "Your hand, Mr. Kiron." I held it out, and with a needle at one end, she pricked my finger.
"Ouch..." I remarked sarcastically. Though it did sting a touch.
"Apologies. This is needed for the binding crest." 
The blood mixed with the ink... or whatever it was in the marker, and she stepped forward to Aya.

"Preferred placement?" She asked me. 
I shrugged. "Uh...standard I suppose." 
Larisa nodded and undid Aya's top, exposing her cleavage. She made a circle on the chest, and inside she put a KS. 'Kiron slave' It glowed and turned black, like a tattoo. "There... till the mark is removed, she is unable to harm you or disobey direct orders. The seal also prevents pregnancy or other changes to her body without the Master's consent. She can still be harmed in combat, however, so be wary of that. She also isn't immune to sickness, so keep her in good health if you want her to last."
Larisa circled back around her desk. As the elf fixed Aya's top, "Or don't... she's yours. Fully and legally." She held out a hand. "It was a pleasure doing business with you, and we hope to see you again." 
I smiled and shook her hand. "Likewise... and don't worry. You will..."
She smirked. "Harem builder? Good, I love repeat customers!"
I chuckled at her quip as I took the leash from the elf and led Aya out into the shop. I needed a few supplies, but first things first. I pull Aya aside. "So..." I started awkwardly. "I... am Kiron. Your...new owner." I tried to sound firm, but my own awkwardness seeped through.
Aya bowed. "Aya. Your slave." She responded. Seemingly unbothered by my failed attempt at being firm, "Or that was my birth name. I will accept whatever name you wish to give me."
"Your birth name is fine. I am pleased to have you, Aya." I said. This time, I let my tone be more genuine. A small purr slipped out of her as her tail twitched slightly. 
"Pleased to serve, master." She said it happily. I gesture to the store before us. "Come, let's get you fitted for gear and a proper slave outfit," I said, noting her rags. She, like the other slaves, wore little more than prison rags it looked like. Aya nodded. "Yes, master."
I took her to the counter and had the attendant take her measurements. While they did that, I browsed the many tools for keeping slaves. I ended up picking up a few things that I wanted to try on Aya. After paying for that and the new uniform and armor for Aya, which wouldn't be ready until tomorrow, I led her home. 
......................................................................
We entered the small, second-floor apartment. Well... it was more akin to a large hotel room... There was a small cooking area, and then the living room and bedroom were kind of the same room. The only bathroom on this floor was shared by the six apartments that were on it. I unhooked Aya's leash.
"Welcome to your new home, Aya... At least till I can get something better." I said. Aya's eyes roamed the room, her tail twitching slightly and her nose sniffing. It was.... lovely... and her master had said it was her home now! She took a few steps in, then stopped. She defaulted to the maid's attention pose, hands together, head bowed. "Apologies master. I was excited. May I explore?" She asked. She knew better than to roam without permission... Hopefully, he forgave her.
I was surprised at her reaction. She really was a well-trained slave. I pat her head gently. "It's your home too now. Yes, you may explore it...." I said. Then I thought about it... best not to be too lenient. She might not respect me if I didn't set boundaries. "However,... you are not to leave the apartment without my permission. Clear?"
Aya smiled. "Master is so kind! Yes sir, I understand... Thank you!" She said it happily. Then she turned to look about the apartment. To most, the simple freedom to explore such a small place might seem trivial... but she had spent the last year in a cage smaller than the littlest closet here. 
...................................................................... 
As Aya checked out her new surroundings, I looked through the stuff I had bought. Some rations for the dungeon delve, a couple of canteens, a couple of torches, and a lantern. All things we would need. Combine that with the bedrolls and packs, and it seemed everything was set. They probably couldn't go too deep yet... but hopefully, they could make enough money to move into one of the houses just outside of town. But that was for another day... Tonight he had a slave girl. His very own... he looked over to her. She was cute as she studied the furniture. He opened the bag of the "other" tools he had bought. "Aya. Come here, please."
"Yes, master!" She said then she came over to the table. She studied the contents of the table. 
"Now..." There was no easy way to start this conversation. "I don't want to force you, but... I did plan on...well..."
"It's ok, master." She said. She held out her wrists. "I appreciate you asking. But you needn't. I know what is expected of me. But if it helps... I consent."