After doing some work and brainstorming the idea of what Gray should look like, I have my prototype.

Will be accepting feedback and suggestions.

Hello Lego!
So revising your sprites, I've noticed a constant issue that you have making sprites, so I hope this quick thing I made will make you understand what that problem is, and most importantly; learn, eventhought I don't consider myself that much of a good spriter. I know this version is a prototype but I hope it helps anyways  🙂

So what I've done first here is making the stand more dynamic, making his legs more open and doing so with the arms, remember these sprites will be in the middle of a fight so they can't have their arms and legs resting like that. Then I coloured the sprite with your palette of colours and shading. Same with the stand pose, I thought these shadows needed more dynamism, to show the muscles, the hair, and the  pants.

Lastly, I used some more vivid colours for the character, getting rid of the boring blank gray, and using some really dark blue and green for the hair and pants respectively, and doing so with the skin colour.

And Ta-dah! There you have a new stand for your character that I hope you like, and if you do and want to use it for the playable version, be my guest!  😁

To Jo4kyx
Here's my thoughts.
I like how you did the sprite by giving it more depth. The hair does have nice detail and the muscle has some definition. I will credit you when he's finished, but also I'm going to make a few changes.

That's alright mate! It's your sprite now after all so feel free to do anything you want with it. Thanks for the credits!

Currently I have ran into a roadblock where I halted progress. I'm trying to decide whether or not I should have Gray transform with his full devil slayer mark. I want to at least have him be accurate to his current state in the series.

Hello Lego, I'm really interested in the project.
In my opinion if it should have that transformation, because, as a wise man once said "little is good, more is better" .

And someone even wiser once said "quality over quantity"  😛

It was me in disguise hehe