Well its mostly about the fate of Foresight. Spoiler In the web novel, Arche actually survives, but becomes Shalltear's pet plaything for a while. But later lives in a small cabin with her twin sisters on the 6th floor of Nazarick. At one point she even teaches Ainz how to dance. Thats everything i know cuz i have read only spoilers too. Havent actually read the web novel. But interesting to know there was a different outcome for the little Arche in the web novel, which was a result of a poll the author made for the fans. Basically the poll was if Arche survives or dies, and the fans voted that she survives. I think or was it vice versa and they voted to kill her in the actual novel. I forgot. I think it was the former.