Hi Magikstyk

Well looking at the tattoo and the fact you are not fond of colour I would recommend the following;

(Positive criticism here and it is only my opinion)

The outline could do ith a rework – there are points where it has become faded and would definitely benefit from a freshen up.

I would also recommend that the tattoo is ‘fleshed out’ with some proper shading and shadowing. The muscles and the body could also be given more definition. This will make the devil be more lifelike.

The fangs could do with some rework to really bring the effect out, maybe add a forked tongue in there.
The eyes really need some pupils (I would suggest slitted over rounded to give it that evil effect).

I would perhaps add to the wings, more shading and maybe some small hooked claws at the tips (similar to a bat) alternatively maybe a wreathe of hell fire along the edges.

Depending on how you feel you could perhaps add a pentagram to the skull region of the devil.

I know you dislike colour but I would suggest at least adding some colour to the halo and flames, even a few hints of it would set it off really nicely.

Well those are my thoughts – let us know what you decide.

Take Care

Matthew