This is a really good stencil!
Diggin' the choice of having purple shadows. As well the shading and muscle details are top notch.

The only real thing I can really point out that could be improved slightly would be the small pieces of white that weren't coloured near the line art.
I realize that this was done with stencil and it would be difficult to completely cover everything with colour without risking overlapped colours, but if you ever touched up this drawing digitally it would look perfect.

Excellent work overall!