Mellifluous1

I have a feeling someone killed by nightblood would likely be either stuck in the CR or immediately go to the beyond. I feel like they could have become cognitive shadows but there seems to be evidence countering this point in Warbreaker itself, with there being deaths by nightblood and no discernable shadows wandering around on the planet. However the way that nightblood sucks at a persons investiture or soul seems extremely similar to the effects of "withering" that the shades on Threnody inflict. Which is why I feel it would make sense for them to become cognitive shadows. Maybe the weilder would become one if they let nightblood completely consume them. Im not certain if this point has yet been touched upon in any of the books or blogs by Sanderson himself.