User blog comment:Das Wunderbar/Bloody Mary - Dead or Unknown?/@comment-24557726-20140709190446/@comment-24557726-20140709210437

To be fair, Fables and their resilience are pretty vague in the game. Georgie is done in by a knife to the stomach, while the Woodsman can shrug off an axe through his skull like it's nothing. The Tweedle dies from being slashed, while Bigby can take a dozen buckshot rounds to his chest and be just fine. Mary pulls a glass shard directly out of her skull, but can't survive being tossed into a wall. Jersey can be stabbed through the heart then have his head smashed in by a heavy statue and be unaffected, but Grendel is permanently incapacitated if his arm's taken off.

It's pretty random as to how much Fables can actually take. Not sure how much their forms have to do with that.