Silence.
I check magic sense for people below, and they're pretty much all stationary. However, one starts to move quickly through the area. Crap, that last guy must have made sound.
I widen my silencing spell to cover most of the warehouse, and I wait for the guy to emerge as I track him with magic sense.
After another moment, I see a floor hatch swing open near where the guards were seated, and another guard emerges while calling out.
"Hey, is everything okay up here!?"
As he notices all the bodies, I activate a max time slow and spring forward to stab him through the front of the neck. Then, with my katana still in him, I pull his body out of the hatch and toss it near his friends. I don't want to scare the kids down there.
I clean my katana on his clothes and sheathe it, shrink my silencing spell back closer to my body, then descend the steps of the hatch.
Below, I can see lines of cages along both walls, there are about six female elves that all look at least 17, with the oldest looking mid-20s, and about 4 wolf-eared children of mixed gender, ages roughly 6-15. It's my first sighting of wolf-kin, and the kids basically look like human children except for the ears and odd hands that seem to have clawed fingers.
Looking around, I don't see any other slaves or guards. Perfect.
I make my way back upstairs and open the warehouse door for air flow, then I drop my time and silencing spells. I do one last check for people in the surrounding area with magic sense, and there are only the ten slaves below me and Nina above me.
I make my way back outside and dispose of the bodies, equipment, and bloodstains around the warehouse with my alchemy spell. I don't want to scare the kids when I take them through here later.
Once the place seems cleaned of evidence, I repeat the process inside the warehouse until I'm similarly satisfied. Looking around, I think it's time to deal with the slaves…err, former slaves, I guess.
I teleport back up to Nina, grab her, then teleport her back inside the warehouse with me. After she gathers what happened, she sighs and messages me.
[Mizuki, you really should start warning a girl before you handle her like that. By the way, this place looks abandoned, nice job!] (Nina)
[Fufufu…thanks, and sorry, I'll warn you from now on. Stay up here while I go negotiate with the slaves? I still need to break their contracts if I can.] (Mizuki)
Nina nods at me with a smirk.
[Sure, sure. I'm curious to see if you can do it. If so, you'll have to explain it later!] (Nina)
I nod back at her, then reapply full concealment and make my way down to the slave cages. I search for the oldest elf again, then I walk over by her cage and kneel. I expand my silencing bubble around just the two of us, so we can talk without being overhead. I whisper to her while still invisible.
"Hey, I'm invisible right now, but I'm here to help you. I've made it so that we can talk privately, since you seem to be the oldest one here. I don't want to scare the children, but I've already killed all the guards in the warehouse." (Mizuki)
The elf girl's eyes go wide in shock, and she jumps a little bit, but then her eyes narrow while she listens. After I'm done, she responds.
"Why should I trust you? For all I know you could be another disgusting human. Plus, our contracts won't let us leave these cages without permission." (…)
That's…not an unreasonable question.
"Well, I promise not to lie to you, so let me start by admitting that I am human. However, I am on your side, and I'm friends with the Second Princess of your kingdom, Ilina Ophelle. I'll even bring you to her after this if you want. I'm going to try to break your contract, then I'll open your cage. I just need you to trust me until then." (Mizuki)
The elf girl recognizes Ilina's name, but she remains suspicious. Then…
"Very well. I don't trust you, but I'll promise to cooperate for now." (...)
That's good enough.
"Okay, the way this spell works should destroy the contract, but it'll also make you completely powerless. Also, I can't promise that it won't hurt or even kill you. I've never done it before, but it's the only way I can think of to help you. Nod if you're ready." (Mizuki)
The elf girl seems to take a deep breath, and then nods.
I will my magic to surround her in a bubble, then I imagine it sucking all the magic inside to its surface. After a moment, I begin to feel resistance, like a vacuum cleaner without enough suction. I pour more magic into my spell, and I will it to attract the magic inside even more strongly.
The elf girl begins to grimace and waver, but I keep going. Eventually, she collapses to the side, but she seems to be breathing. After a few minutes, she recovers enough to sit back up.
Time to check if it worked.
"I'm sorry to do this to you, but I'm going to open your cage now, and I want you to check if you can leave. I need to know if the contract was broken." (Mizuki)
The elf girl nods. I use my enhanced katana to cut the lock of her cage, then I drop all my spells except body enhancement. I pull her cage open and step back.
Now being able to see me, the elf girl's eyes open wide. At this point, the other slaves have started to notice as well, and a lot of whispering is going on.
The elf girl takes another deep breath, then starts dragging herself out of the cage. After a second, she's out fully, and she slowly stands up to face me.