See that point that is jutting out from his back?

What bone do I envelope that vertice to make it look normal? Currently it is weighted to bone_ribcage. I have tried a few other nearby ones and it did not fix it. Or is it a problem with mace's animation?

Doesn't look abnormal to me; my shoulder blades stick out like that.

Well, on mace's model it doesn't happen, and it looks really ugly here regardless.

Alright then, I guess. In that case, since those are basically the shoulder blades, they should probably be enveloped to the clavicle bones: bone_l_clavicle and bone_r_clavicle.

I tried that, but it did not change anything (visibly). I think I might have to add more edges. I will get back to you in the morni

EDIT: fixed it, I had to envelope that point and a point in his armpit to the clavicle, I also had to go into solo mode to remove some bone_ribcage weighting

Depending on how the vertexes line up with bones and weighting small things like this can happen sometimes. It's pretty unavoidable if you have a low-poly model and you want to keep the enveloping accurate.