So, there's a few things I've been wondering ever since Way of Kings. My original understanding was that all ten orders of Knight Radiant were of Honor, but further reading and Wyndel changed that for me - now it seems that there are 5 Honor-based and 5 Cultivation-based Knights - that is to say, 5 orders for spren of each shard.
But there are three shards on Roshar, not two. This leads me to think that there are possibly 5 more orders, based on Odium-based spren, and that those five orders, and that there are five additional surges corresponding to it, for a total of 15 knights and 15 surges - and the double eye becomes a triple eye - or rather, the third eye is added. Then the thing with Renarin happened. At first, in Words of Radiance, I thought this evidence for the theory. But then we saw his spren, and the concept of a "corrupted" knight order came into being... and my theory shifted again. Or maybe perhaps now there's two competing theories.
Now I see an order as having a bond between two surges - one from Honor, and one from Cultivation. Adding in Odium into the mix adds a third surge, possibly one of the hypothetical five from odium. I also wonder if that the sibling of the Nightwatcher and the Stormfather became one of these corrupted spren, and that's why the Stormfather won't speak of it to Dalanar (well, that or it was betrayed in the Recreance).
What are y'alls thoughts on these two ideas? On the Third Eye with 15 Orders, or corrupted orders having 3 surges?