Vector Prime and The Fallen... considering the frequency I draw them, one might say that I'm a little obsessed. Well, maybe, but I like drawing Fallen's flames and Veccy's face, and they're one of the few things I can draw without reference -- so when I start do dabble something without having any clear original idea I tend to fall into drawing them.
They didn't meet anywhere in canon in these forms, at least until now and as far I know -- which isn't so much to tell the truth. But I like to imagine...
Pencil sketch, pencil lineart, color and montage in GIMP.
(I published the lineart on my LJ some times ago.)