I have Enderal: Forgotten Stories downloaded via steam with no modifications beyond what steam automatically installs as a part of it, am running through my first playthrough, and have come across a persistent CTD during the "A Song in the Silence" quest.
Specifically, I am near the end of it (I assume) in the "cave under the waterfall" location where he shows you a painting, I progress through the following dialogue, he transforms into a monstrous entity, I kill said entity, the world starts deteriorating, and then the game crashes to desktop. This has happened about 4 times in a row now. I have verified the game cache, I have loaded a save a bit further back, and each time I get the same result.
Attached should be some save files, with 44 being in the powder desert before I arrived in silvergrove, 45 being in silvergrove (I believe I was searching for moths at that point), and 46 being made in the middle of the final conversation with Rynéus.