Armature warps and skews model?

So I’ve been teaching myself how to use Blender for the past week, mainly by toying around with assets, and so far everything’s been going fine, I’ve been mostly using renders as art reference for fan art and things like that.

Only for some reason I CAN’T get this armature to work! I even tried assigning it manually and no matter what I do it skews and warps the mesh and just looks awful, I don’t understand at all what I’m doing wrong, I did this for two other previous models and they worked perfectly fine, so I’m pretty stumped, and I haven’t really been able to find a solution.

Does anyone know what could be wrong? Attached is the file.

This is what keeps happening:

CELLSOLDARM.blend (1.84 MB)

Just keep in mind, in the file only the left arm is manually assigned currently, since I wanted to test to see if manually assigning it would fix my problems.

Turn the bone display to Octahedron. You see the problem right a way. Bones are squished in Z scale.

Select the Armature object in Object mode, then hot key [Ctrl][A], choose scale to fix it.

Wow, I don’t even know how the armature got set up that way…

But thank you! It means a lot!