Nightblood is essentially a minor Shard

[Ketek]

The title essentially says it all, so I'll get to the why.

 

We know that Shards require a sentient mind to be attached to their power, whether it's that of another being or one it created on its own.

 

Well, I think that Nightblood essentially requires the same. Shashara tried to give it the ability to rationalize and think, but it didn't work because the invested Breaths gave it more of a Spiritual, rather than Cognitive presence, which I think could have been the original intent. Thus, you end up with a extremely powerful sword that lacks the context to fulfill its intent - destroy evil.

 

This is where the cognitive mind of another sentient being comes into play. Like Shards require holders to bear their power, Nightblood does too - the mind of its current holder focuses the intent and provides a context to the concept of evil.

 

Simply put, every time someone picks up Nightblood, we're witnessing (on a much tinier scale) something not so different from what Vin or Sazed did when they ascended.

 

Simple, I know, but it just struck me and I had to share.

[bartbug]

I've been thinking about this for a long, long time. Yes.

 

This is part of why Nightblood is so messed up. All Shards have a simple, fundamental, thought-free goal; Ruin, Preservation, Odium... Morality doesn't come into it. Nightblood, however, is founded upon morality, without being granted an inkling of what that morality is.

[RShara]

I'm pretty sure Nightblood is considered a Splinter of Endowment thanks to the amount of Investiture he has.

And since

spren are considered Splinters, and sprenblades are less powerful than Nightblood,

it is safe to call Nightblood a significant Splinter at that.

[Tempus]

Nightblood is indeed a splinter, and a very powerful splinter. This has been indirectly but clearly confirmed.

[Ketek]

Interesting points about it being a Splinter. I hadn't thought of it that way, but it does make sense. And if Nightblood is a Splinter of Endowment... wouldn't it be the first man-made Splinter, where others were all created by the parent Shard? And if so, can one create Splinters for other Shards, or is it unique to Endowment alone, given its intent?