You've basically not given us anything but a conceptart of Mysterio? I think you should probably have some conceptart made for the
actual character you'll be using.
There are plenty of isometric pixelart games and you shouldn't have a problem just googling it and find some sort of isometric reference.
I don't mean to be rude(If you are serious about creating a game), but you can't ask anyone to help you out of you don't even post any sort of work you have done. This part of the forum is for posting you pixelart and recieve feedback, not asking for help without presenting any sort of work related to the actual sprite you are looking to get help with. We are not the concept artists, we are merely here to help you improve, not create things for you.
You often get a better character if you do some pre-work, concept art, writing something about the character/short biography, what type of person it is, what clothes are appropriate for his mission. etc.
Here are some references: