Does killing a spren erase only their Identity, or does it damage their SpiritWebs and Connection. Or something else entirely?

[GunslingerRadiant]

Many of the spren in Roshars Cognitive Realm describe deadeyes as robbed of their minds, however RoW contradicts this in Adolins trial. So what actually happens to deadeyes? What part of them is damaged that lets them be summoned in the physical realm, but keeps them from thinking? 

[Quantus he/him]

We dont know what happened to Deadeyes. We do know that it did not happen before the Recreance, even when the Radiant broke their Oaths, so Something Changed but we dont know what it was yet.  There are theories that that the same BAM imprisonment that damaged the Singer Connections to make Parshendi also affected the Spren/Radiant Bond enough to cause Deadeyes to form.  Other theories (mostly following the Trial events) suspect that there where some more specific and intentional steps taken by the Radiant Spren back then to make Deadeyes form for a specific Purpose (such as creating a 3rd set of Surges based on Cultivation and Lifelight). 

[AlastorBM He]

Well, it is a somewhat complicated question, we do not know the details of the breaking of their oaths or how this specifically affected them beyond what we see.Since we are on topic here I will speak with spoilers but be careful. 

Spoilers!!!!! from RoW

Maya's case is different because of the bond she has with Adolin, but it is something extremely rare, since thanks to that she recovers some reason. In shadesmear Spren can think like humans, but in the physical realm they need a  nahel bond, We could say that by breaking the oaths the damage went much further than what happened to Syl. For example. 

talking about the Deadeye

We could say that when the "connection" with his radiant was damaged, his "identity" was also damaged. If it is a 4th or a 5th oath, the link is very strong (so strong that not even a fabrial can interfere with it) I would personally say that his spirit web is only one in the 5th which would make the damage make sense. 

I also have to add that their sword form in which they are stuck is how they were after breaking their oaths, that is the "physical" form, let's say, of the investiture.

Quote

Overlord Jebus

All the physical manifestations--solid physical manifestations we've seen of Investiture has been metallic. It's been atium, lerasium, Shardblades. Is that just a coincidence?

Brandon Sanderson

No, it's intentional.

Overlord Jebus

It's intentional so we're not going to see Investiture wood or Investiture plastic?

Brandon Sanderson

Right, I mean technically, like, what do you call the aethers? Those are not metal. But I do it as metal intentionally.

Questioner

They could be a metal with very low boiling point.

Brandon Sanderson

*sarcastically* Yes, the vine ones are--

Overlord Jebus

Well we've had liquid, we've had gas, the solids all seem to be metallic, so.

Brandon Sanderson

That is intentional, it's just one of those little laws of the cosmere, that's not meant to mean anything

Emerald City Comic Con 2018 (March 1, 2018)

And from coppermind

Quote

Investiture transcends the three realms: Physical, Cognitive, and Spiritual Realm that compose most of the cosmere. However, it is more Spiritual than anything.In the Physical Realm, Investiture is known to exist in solid, (i.e. atium and lerasium), liquid (many perpendicularities), and gaseous material forms (Preservation's Mists, Light, BioChromatic Breath). For some reason, all solid Investiture is metallic, the result of one of the laws governing the cosmere.

 

 

I hope it helps!

 

Edited June 9 by alastorBM
bring more info