Can Nightblood be considered a Splinter and does it function like a spren realmatically, are there distinct differences is what I'm asking.
Nightblood is kind of his own strange thing. He's an attempt to use one magic to replicate something in another. He's closest to a spren, but kind of like a...robot spren, for lack of better words to use.
When you say that Nightblood is "an attempt to use one magic to replicate something in another," do you mean life in general, or are you referring to a specific effect in a specific magic system?
There are those involved who knew that Shardblades existed before they tried the Nightblood experiment.
So does this mean Vasher had knowledge of Shardblades before creating Nightblood?
It means what I wrote, and nothing more at this point. :)
Dude. That's the most tantalizing RAFO I've seen in awhile. Have other Shards made Shardblades besides Honor?
Is that why Vasher uses the word 'Investiture' instead of some personal term for it?
I could be wrong, but I think Vasher was the first one in any book I allowed to use cosmere-aware terms for speaking of things like the magics. (Investiture is one of these.)