Hrm... The black line thing might be an issue when you start placing it in an environment. Could happen that it'll feel like it's not meant to be there. We can't really judge that until we see mock-ups. Try a non-outlined version just in case.
As for the blade, will it be spinning? If that were the case it might be better to have lines that run around the surface. Most likely from wear and tear it'll develop scratches as it spins. It'll also give the suggestion of brushed metal or something similar. Here's a rough version of what I mean.
Great work on the characters. The choice of hairstyles, postures, and clothes are of a consistent style yet each is pretty unique. Hoping to hear more updates from ya.
