But if you for example have a body and an arm on separate layers and the gradient would be filled over to the arm yuo see a line ( Well you use a invisible line but you will se that anyway ).
You can of course paste the arm to the body but it you want to use them on separate layers are any way to make it work
Or if you want a gradient over the entire character, why not isolate the shape of the character and use an inverted cutter that references a big shape filled with the gradation you want?
Do you mean that you want all of the parts to share the same gradient and look like they would if they were a single drawing on a single layer filled in one pass?
I tried a few things like the Gradient Module which seems to only work like a Colour Card rather than on objects but the closest thing I could come up with was drawing a character on one layer without breaks between limbs, filling with a gradient, cutting and distributing the pieces to layers.