But it's definitely anime. I looooove this game and the art style. I think the method of how to do it is the easier part. It's the body proportions and style of drawing that you would have to practice. Practice on paper first. The easiest way to do it is copy the artist's drawings over and over again to get a hang of his style then apply it to other figures. But I suggest finding your own style as copying won't do you much good in the long run.
what about its line? do you know how to do it? what's the name of it?
There's no name for it, and doing it is a matter of understanding form, line weight, and whatever tools you're using.
You're not going to find a tutorial specifically for making this sort of line, because that would be a stupid thing to learn. Get good at drawing and this will come along with that. This thread should help you get started. A lot of it is just setting your priorities so that you know what and how to practice and study. Yours appear to be rather misguided, and I think that thread should help you figure out what you need to do.