Okay I think the spoiler warning should be self-explanatory, but yeah. Leave now if you haven't read both books.
Anyways, we know from the epigraphs that Rayse (who I think most of us are assuming to be Odium) killed Aona and Skai, the Shardholders on Elantris, and then proceeded to Splinter their power so they couldn't be taken up by someone else and used to oppose him. Now we also know, from Dalinar's visions, that Odium killed the Almighty, who seems to be his prime opponent on Roshar. Given that Odium doesn't seem content to just kill Shards he views as a threat, but Splinter them so a successor can't inherit them and use them against him either, I think its a definite possibility that Odium Splintered the Almighty's Shard after killing him. After all, even though its only the first book, there's nothing to indicate yet that the Stormlight Archives will involve any single character seeking or holding the Almighty's Shard to oppose Odium...but we have heard an awful lot about 'Uniting them.' Now, we don't know WHEN in the timeline Odium killed the Almighty but we do know that while the Almighty wasn't as good at seeing the future as others like Cultivation, he did have some ability to see the future...the closer the events were to him, the clearer he could see them. So point is...we don't know that he was actually even still around at the time of the events Dalinar saw in his visions. The betrayal of the Radiants, etc. Just that he'd seen them, either as a personal witness, or in visions.
So basically, what I’m proposing is…what if Odium killed the Almighty BEFORE the founding of the Ten Orders and the Knights Radiant? What if, similar to how he treated his possible rivals on Sel, he not only killed the Almighty, but Splintered his Shard to keep anyone else from raising it up against him? Could the Ten Heralds and the Ten Orders hold or tap into the Ten Splinters of his power? Think about it, Odium means hatred and disgust, essentially the worst emotions sentient beings are capable of. Not all the Shards are supposedly paired as polar opposites, but some like Ruin and Preservation are, and unless Adonalsium was a less than great guy or force himself, and leaned towards the negative (something I find hard to believe considering Hoid, a seemingly good guy, seems to have some desire to see Adonalsium reconstituted) - then that means Odium has to have an opposite number to balance the scales, and represent all the good and best emotions and traits sentient beings are capable of. Now I realize this is a lot of conjecture, but this is all speculation anyways, but if Odium does have an opposite number representing the best of sentient beings, the Almighty is are best bet for being that Shard, given his power, opposition to Odium, and the fact that both of them seemed to make Roshar their home.
And what are the Ten Orders of the Knights Radiant? Well we don’t know all of them, but we do know they’re dedicated to the protection of humanity and represent positive ideals. At least one of them, the Windrunners, is dedicated to the pursuit of Honor. Another of them, the Soulcasters, seems to have some relation to Truth given the emphasis Truth is given in the book from Szeth the Truthless to the unknown (Truthspren?) requiring a Truth from Shallan…perhaps Soulcasting requires a personal Truth be exchanged each time one changes the True nature of another object? If Honor and Truth or Honesty are two of the Ten Orders….might the Ten Orders each hold or be powered by one of the most positive traits beings are capable of? And thus make up Ten Splinters of a Shard that embodies all the best traits in creation? The Dawnshards the Almighty speaks of could be the actual Splinters, or the Splinters could be the Dawnblades of the Ten Heralds, as we know they’re different from actual Shardblades. Regardless, if any of my theory is true, its most likely that the Ten Heralds or that which powers them is the individual Splinters which they then in turn pass down to the individual Order of Radiants that they correspond to.
Unite them then….unite the high princes perhaps, or unite humanity, or unite humanity and the parshendi…or unite the Ten Orders, the Ten Splinters and recreate the power of the Almighty’s Shard as close as possible?