Nightblood's durability

[Faceless Mist-Wraith he/him]

How tough is Nightblood? Does he only have the durability of a normal sword, or is he different because he is Invested? What would happen if someone did manage to break him?

Minor side question: Can Nightblood rust?

[Modal Seoul he/him]

Nightblood is very tough. Brandon has said that he could absorb all the Investiture in the Cosmere. If Nightblood could even be broken, I think that all the Investiture that he has corrupted will try and possess something else. And no, Nightblood cannot rust, because he is an Awakened object of steel.

[Pagerunner he/him]

When Nightblood is out of his sheath he's creating black smoke, which will be pushing air away from him. That's bulk mass transfer, while you also need transport of water vapor molecules through the air to the surface of the blade to create rust. I don't think he'd be able to rust, even if it was just because his blade is protected from oxidizing agents by the manifestation of the smoke.

Probably not the answer you're looking for, though. Nightblood is very much like a Shardblade, and we've never seen those break, even when a Shardbearer used one as a springboard. (I think it was Adolin in WoR, but I'm not sure.) I'd expect the Investiture to provide additional coherence, to keep Nightblood from breaking or deforming, but that's not a given. Especially if Nightblood is rarely used as an actual sword, in which case he wouldn't need to be indestructible. (Although the sheath is definitely sturdy enough to be rammed through someone's chest.)

[Weltall]

We know that Nightblood is about the most heavily Invested object we've seen in the series so far, in the context of a 'What would be the hardest to Push/Pull on Allomantically?' question. Taking that and material from other works we can speculate that Nightblood probably does not rust and is probably functionally unbreakable.

Rusting (Mistborn Era 2)

 

We know that Hemalurgic spikes are considerably less Invested than Nightblood, yet these can remain intact and effective for at least thirteen hundred years in the case of Kandra spikes and at least three centuries for Inquisitor spikes (including a larger variety of metals) with no evidence of rusting and no power loss other than what happens naturally if they're left outside a body for a length of time. We do know these spikes can be physically broken but since they're not nearly as invested as Nightblood we can't really use that to generalize about the breakability of all Invested objects.

Breakability (Stormlight Archive)

 

When Szeth points out that he needs a Shardblade if he's going to fight opponents with Shardblades and Honorblades, Nale gives him Nightblood and seems to think that there will be no problem with the weapon in fighting against swords that cut 'dead' matter like tissue paper. We know Brandon has called Nightblood functionally a Shardblade, just orders of magnitude more powerful. Ergo, it seems safe to assume that if those can't damge Nightblood, there's nothing more mundane that can either.

Edited March 30, 2017 by Weltall

[Faceless Mist-Wraith he/him]

I was wondering more along the lines of "If you put Nightblood on two braces, and then hammered it with an immensely heavy object, what would happen?". I didn't know whether being heavily Invested would affect the situation.

As for rusting, I guessed that it would actively destroy an rust that formed, but I wanted to ask to see if anyone had a more solid answer.

[Farnsworth]

Nightblood is invested enough that he probably exists enough in the Cognitive realm where he would only break if he thought of himself as being broken.

[Weltall]

@Figberts Very good point. Aside from Nightblood, the only thing more Cognitively secure in its self-image and thus absolutely immutable is of course Stick.

[Elenion he/him]

Can cognitive security lead to an object resisting damage? I'm a little skeptical.

Emperor's Soul:

Spoiler

When Shai is in the cell, she talks about how the room wants to be beautiful like it once was. But yet despite the room's cognitive view of itself, it had fallen into disrepair.

 

[Weltall]

40 minutes ago, Elenion said:

Can cognitive security lead to an object resisting damage? I'm a little skeptical.

The room isn't Invested though, Nightblood is. And Stick is of course Stick.

TES

 

Shai's various Forgeries tell the parts of her room that it is beautiful, which then make it beautiful, and these changes stick until she either modifies them or someone removes the stamp. I'm not sure we have WoB on the matter but I suspect that attempts to damage a stamped object would encounter some resistance from the Investiture, until the Dor gives up and the Forgery fails as if the stamp had been removed. We do know for a fact that the stamps themselves are more resistant to change than the ordinary properties of the objects being stamped would seem to indicate.

Edited April 1, 2017 by Weltall

[Farnsworth]

And Shai does have to force a bit to break the soulstamp, because it's invested a bit.