I'm not sure this in intended, but yesterday I cast Wall of Fire, and an enemy standing in the lava took fire damage at the start of his next turn, and then received a card from Martyr's Blessing. Although the lava was created by me, it is not controlled by me. So I thought it would not trigger a card draw now that only enemy controlled cards are supposed to. I suspect it is a corner case that was left behind after the change in the operation of Martyr's Blessing. But maybe it is meant to be this way, so if so ignore this post. (If it's meant to be, maybe the text should be changed to 'takes damage from a card not controlled by an ally').
Pfff, if I controlled the lava I would tell it not to burn me! But fair enough, this is how they have decided to work it.
Good reply Gerry. I read Jon's post about this " - I just liked the idea of self-damage and wanted to see if it could be contained." Thats a nice idea but sometimes it gets ridiculous when a character can have double or even triple the regular amount of cards. Perhaps limiting the duration more would be better here. EDIT: Read a bit more. I find that the best solution be a roll for every time damage is done. 50/50 seams right. That way it will be a wager to how much you risk abusing this card.