Hmm, for a Crypt Ghoul I'd certainly go for making the blade look very used and possibly uncared for.
If you don't actually want to go with blood simply making the blade look old worn and a little rusty would probably make it fit in a lot better. That's fairly easily done with browns and a little orange, or simply using inks/washes.
For blood I think it would still benefit from looking manky and grimey. Browns, dark reds rather than bright red blood splattered everywhere, though a little bit of brighter red, possinly with a little gloss varnish if you wanted to make it look newly used and wet.
Naturally you could go the whole way and do both, rust up the blade then apply a dried on gore look.