Nightblood mechanics

[Theodore Smedry]

I have some questions about Nightblood that I haven't quite found answers for on Arcanum (although I haven't scanned all 222 WoBs tagged "nightblood") or in the cosmere books:

1: Does Nightblood need a direct connection to a source of investiture to consume it (e.g. consuming Breaths/Stormlight from someone holding it vs. it lying on the ground and consuming ambient investiture)? I know Brandon has said Nightblood can only consume kinetic investiture, but he also said that it can consume the mists so I'm not sure where the line of what Nightblood can and can't consume is.

2: If Nightblood interacts with the Spiritual realm, why can it not consume all investiture in that realm? I bet this has something to do with Connection and who is holding it, but I'm not sure. My knowledge of how spiritual mumbo-jumbo works is limited.

3: If Nightblood consumes enough investiture, would it become a perpendicularity? If so, would someone be able to use it without being consumed or is it more like a black hole with an event horizon?

4: On the black hole analogy, is Nightblood's investiture slowly dissipating like Hawking radiation?

5: Since Nightblood deepens colors around it, is it converting all the investiture into Breath or some other form of Endowment's investiture?

Edited September 5, 2019 by Theodore Smedry

[Karger]

7 hours ago, Theodore Smedry said:

1: Does Nightblood need a direct connection to a source of investiture to consume it (e.g. consuming Breaths/Stormlight from someone holding it vs. it lying on the ground and consuming ambient investiture)? I know Brandon has said Nightblood can only consume kinetic investiture, but he also said that it can consume the mists so I'm not sure where the line of what Nightblood can and can't consume is.

Nightblood takes stormlight from the light Szeth is carrying with him in Oathbringer(this is prior to him becoming a skybreaker) so apparently that is good enough.

7 hours ago, Theodore Smedry said:

2: If Nightblood interacts with the Spiritual realm, why can it not consume all investiture in that realm? I bet this has something to do with Connection and who is holding it, but I'm not sure. My knowledge of how spiritual mumbo-jumbo works is limited.

First of all Nightblood has limits.  He was made by "humans" and exists in the "real world."  Consuming everything in the SR does not seem like a probable thing he can do.  Nightblood destroys the physical cognitive and spiritual aspects of the entity he is used on when he kills them.  He also powers himself off of your natural investiture if you run out.  That is it. 

7 hours ago, Theodore Smedry said:

3: If Nightblood consumes enough investiture, would it become a perpendicularity? If so, would someone be able to use it without being consumed or is it more like a black hole with an event horizon?

Unknown.  According to Brandon if you get enough investature in one place it will form a perpendicularity and Nightblood is the most invested object in the Cosmere(and is becoming more so).  Make of this what you will.

7 hours ago, Theodore Smedry said:

4: On the black hole analogy, is Nightblood's investiture slowly dissipating like Hawking radiation?

Some black smoke does leak off of Nightblood when he is being used.  Brandon called this corrupted investiture.

7 hours ago, Theodore Smedry said:

5: Since Nightblood deepens colors around it, is it converting all the investiture into Breath or some other form of Endowment's investiture?

All of what investiture?  Nightblood does this because he is super invested.  Pretty much everything made by awakening does the same.

[HSuperLee]

1. As far as we have seen, Nightblood requires direct physical contact to feed on something's investiture.

2. Nightblood consumes across all three realms, but the spiritual realm doesn't really have space or substance the way we think of it, so it only seems to consume the souls of things it can physically touch for, as you said, spiritual mumbo-jumbo reasons. Also, all the investiture in the spiritual realm would be all the investiture in the universe, and I (despite many disagreeing with me) do believe that Nighblood has relatively low limits as to the amount of investiture it can consume.

3. Theoretically, and likely, as entering a perpendicularly does not instantly transport you to another realm.

4. Yes. That is what it's black smoke is.

5. Potentially. We do not fully know how Nightblood works. The only person who did is dead.