A couple of thoughts, will probably be long. Grammar Nazis beware.

This is quite long. Don’t press the plus unless you want to be greeted bu a whole ton of text. Once again, don’t press it unless you want to read some random thoughts.

Before I start, I just want to say that these are all just thoughts and opinions from what I’ve read so far. Feel free to disagree, other people’s opinions are always interesting. Also, I forgot many names. I’m just like that.

As been stated by many, but cannot be stated enough, #15 is precious and although he can likely do it himself, should be protected.
Bruce is an asshole. Enough said, moving on.
Mr. Guard is an asshole. But he’s also trying to keep his job. So idk if I should hate him. I probably should.
It’s been established that mc is likely either normal height, or pretty short, but either way, #15 must be huge if the size of his demon is the same size as his physical human body.
White/silver haired guy is a mom.
Speaking of him, he is totally going to end up with the guard dude, it’s easy enough to see. The tropes are all there waiting to be used. Wondering how it will fit in the grand scheme of things... or maybe it won’t and will just be a side story.
Something in me wishes for pure fluff where mc and #15 leave the prison thingy and live life together quietly with mc’s mother and just live wholesomely. That wouldn’t make much of a story though... but a 4koma side story would be cool. Not going to happen though. Probably. (I could dream.)

Nitpicking ahead. Beware. It’s all probably explained but I glossed over it while reading, lmao.
So why do the prisoners have their hands on a key? Isn’t it kind of dangerous? And wasn’t it stated that the key that could mold into the heart lock thingy kinda precious or something? Or at the very least, mc should’ve felt some pain as was established in the beginning.
Speaking of the beginning of the story, did they literally just start using the locker room or something? Why does it take so long for the others to find out about his heart lock?
I might have glossed over this in the beginning but why does mc let Bitch (Bruce) go into the heart lock or whatever if he knows about the fantasies in there. Was it his way to confess or something? Not very smooth though, as I’m sure that people don’t like to be confessed to via the perverted fantasies of the confessor. I’m not siding with Bruce here, he’s still an ass, and his reaction was way over the top, to understate it greatly, but mc should’ve maybe thought about it a little more. Then again, teenage hormones. Enough said.

A couple of questions
Where do heart locks come from? Were people just born with them? If so, how can you upgrade it? And how did prehistoric people open them? And what’s the difference between A-E? Is it quality? Or is it like blood types?
What even are demons? Is it like a physical manifestation of a person’s bad thoughts? And what are the requirements to have one? Do you need to do something extremely bad? Or have an extreme level of negative emotions? What are they made out of? It’s been shown that they can physically manipulate things and are stronger than regular people. Also, idk if this really happens or if this is my sleep deprivation saying hello, but can’t they shoot like, little bullets of themselves out or something? How does that work? Do they get those parts back or are they regenerative?

Thanks for reading this excessively long comment that has a bunch of random thoughts, goes way too far into what is likely a simple story, and asks questions likely answered in the story.

And finally, if you are still here (which will be nobody) ... raws?