Discuss Divinity Original Sin, as well as comments posted to our Divinity Original Sin Wiki and Divinity Original Sin 2 Wiki
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On Definitive Edition, inspecting the altars now adds a lore entry called The Eternal Promise.
Also awakening the heroes at the graveyard adds to to the same lore
Definitive: The three altars all add entries to "The Eternal Promise", which I already had in my log as a Chronicle from Ft. Joy, iirc. There is an entry about Zaleskar under this heading. Contrary to other posts, despite having a similar message this had nothing to do with scarecrows, and no Source points are refilled by using the altars.
In Definitive Edition, interacting with each altar for the first time and praying there WILL refill one source point for the character doing the praying. Then again, that might be a specific thing for Fane, as I used him to interact with them.