TruthlessShin

My theory has always been that most Spren are just the cognitive representation of everything. For example, flamespren are the representation of how the flame sees itself, hence it freezing in a state that it has been recorded in. Something about the magic of roshar, probably having to do with honor being splintered, has allowed the Spren to represent themselves in the physical realm, at least in the area where honor was splintered. Since all Brandon's (non-YA) books are set in the cosmere, maybe every world has Spren that usually stay in the cognitive realm? That being said, my guess is that all the Spren we've seen in the physical realm are somehow related to honor, while the ones we've seen in the cognitive realm (deathspren, the ones shallan sees, etc) are related to cultivation.

So I was reading through the book today and caught this: "The Shardbearer stood with his blade resting on his armored shoulder, and he inspected Dalinar with eyes of such bright blue, they were almost white. We're those eyes actually glowing, leaking Stormlight?" -page 371 softcover Slightly off-topic, but I wonder if Hoid's comment has something to do with lighteyes being able to hold Stormlight in some way.

(warning, mistborn spoilers below) Ok, here's an idea: maybe the majority of spren are like the metals were in mistborn... Not representative of either shard in particular. But, there are some like honorspren (and apparently cultivationspren) that are. These would be like the atium and lerasium of those shards. It works too, seeing as syl imbues kaladin with some powers of honor in the same way lerasium imbues the person with preservation's magic, allomancy.

I like this idea, especially if you combine it with the theory that Hoid's letter in the epigraphs was addressed to a dragon (which comes from him calling the recipient 'you old reptile'). And I had never thought about what the greatshells could become... Maybe that has something to do with why the parshendi started the war?

Regarding the reason behind szeth's punishment. I believe the title 'truthless' is the big hint here. Remember that shallan has to speak a 'powerful truth' in order to gain access to shadesmar. So it is likely that szeth either entered shadesmar himself (possibly this is against shin law) or committed some illegal act using shadesmar. Either way, it gives szeth the ability to access it. Once he (inevitably) frees himself from his imprisonment.