I have a fair number of headscratchers about this game..

[Hunter of Shadows]

The wine is revealed(by FG, dunno where) to be spiked by a potion that acts as a summoning for eldritch entities from Alexander's realm, the entities try to twist the human bodies into forms they are more used to, of course this can only be done so much, thus why Alexander had to reinforce their bodies with robes/nails to keep the gatherers from falling to pieces