QUESTION (PARAPHRASED)
So what happens when Shards die?
BRANDON SANDERSON (PARAPHRASED)
Well, it depends on how long the Shardholders have held the Shard. After they die, the Shard is often able to continue acting, a kind of "Cognitive shadow". For example, the mists were able to continue doing what Preservation wished in helping out Vin and snapping people. With the Stormfather, he is that Cognitive shadow, and he's semi sentient. It's that power, but no one is actually holding it. We also see this on Threnody.
I'm new to the forums and don't know if this has been discussed, but is Ati's cognitive shadow still around? By the sound of what Brandon said above it seems like he's definitely held his shard long enough to form a cognitive shadow (since Leras died thousands of years before him and he had an ok functioning CS).
Could his shadow still be around during Era 2? Could his shadow have picked up another shard, perhaps one killed by Rayse, and is back to destroy the world?