It was sometime since he had arrived here, and another when he was forcefully fused with what can be considered records from across timelines from this place.
*It had ben some time since he had arrived and longer since he was forcefully*
He remembers everything, the wars, the Grand Order and so much more. And so, he weeps and prayers for more and more punishment as repentance here in what can surely be hell as demons prowled the halls outside his cage. All of them in different forms, some humans, either humanoid to a perfect replica with some changes on the scale to truly horrifying things that he can barely wonder how they function, before dismissing them as Demons never truly make sense, the Demon Pillars being a good example of it.
This entire paragraph slipped to present tense, when the beginning was in past tense, so:
*He could remember everything, the wars, the Grand Order and so much more. And so, he wept and prayed for more and more punishment, as repentance, here, in what surely was hell as demons prowled the halls outside his cage. All of them in different forms, some humans, either humanoid to a perfect replica with some changes on the scale, to truly horrifying things so strange he could barely wonder how they functioned, before dismissing that as Demons never truly making sense, the Demon Pillars being a good example of it.*
Some other little changes to the thing:
-Knowing where to put comas is difficult and this time you didn't have enough in the second sentence. An advice I can give is to try and tell the sentence out loud, but that requires knowing the normal rhythm that English's supposed to have... which I can't be sure you have yet. Well, in that case I can tell you that practice makes perfect, continue writing and reading in english in a real life environment like you're doing, learn from your mistakes, and you will become better. Another little advice about learning any language I can tell is this: Try to stop Translating to do it, the language is independent of yours and learning how to speak it as such is how you get really good at it. Not that it's easy, but, once again, practice, practice, practice.
-Same little problem with a *missing* coma in the third sentence, also, the *barely wonder how they functioned* was missing a little thing before it to make the sentence flow correctly, added a *so strange*.
It's wings, large enough to form a shield around it's body
It's claws were sharp enough
Its in all cases, it's is the contraction of *it is*, its is the form of it equivalent to his/her/their/your and since we're on your and it's a very common mistake too, you're is for you are, your was just explained.
And don't worry, native speakers make these mistakes all the time too.
Alongside, in one word.
he would also see what he could infer as fellow damned souls
Technically, would can be correct here, and that's one example where Grammarly wouldn't help you, because it's better to use could.
Let me quote Encyclppedia Brittanica on that one:
*
Could is used to say that an action or event is possible.
Would is used to talk about a possible or imagined situation, and is often used when that possible situation is not going to happen.
Should is used to say that something is the proper or best thing to do, or to say that someone ought to do something or must do something.*
they did seem rather doll-like than humans
Either move the rather to after doll-like or replace it by a more here. Both works, don't have the exact same meaning, but it's close enough as to not make a difference.
however, their screams of pain was real,
Were, not was, you are using Screams as the subject, so plural and not singular form.
Never his, for this is where he would belong for all his sins.
Sentence changed to present tense here, the first is should be was, the rest is good (and technically, the sentence was good, it's just that the rest of the narration is in past tense).
the most you heard was 'Abnormality'.
*the one he heard the most*
Hmm, could that be why they refer to the Demons prowling around?
How instead of why.
Odd but every being has their way to refer them but he will not judge, nor will he condemn them for warily looking at him, not once going over to open.
You slipped to present here, and *their way to refer to them but he will not judge* don't flow well:
*Odd, but for every being there was a way to refer to them, so he would not judge, nor would he condemn them for warily looking at him, not once going over to open.*
I have to admit the first part had me a little stumped on how to make it flow because it's not how I think, so doesn't come easily.
It's the lest he deserves for what he has done.
The least; and had instead of has, still past tense narration.
for he deserves this and more.
Deserved.
Alas, Gille will know that will never happen to him.
Knew instead of will know. You are talking about something the is true in the present in a past tense narration, not something in the future.
Well, finished, I do get the feeling you got a little better, so there's that.
Or I could be getting inured due to the exposure, one of the two.
Edit:
I've said it once before
Gilles as a caster looks like a frog about to jump face first into a wall
The way his eyes are just brings it to mind does it not?
If I had to guess, he's actually inspired by the fish people of lovecraftian literature rather than a frog.
edit2:
As a funny little example of the fact that your/you're its/it's is a really easy mistake to make, I just had to correct one in my own explanations.