After resolving the dark arts cards and villain effects, my character has 1hp. That same character has the "potions" proficiency, so if he plays a spell, ally, and item, any hero gains a hp and a zap.
My character does indeed have all three types of cards in his hand and will be playing all of them. However, the "diary" horcrux is still in play, which says "Each time a Hero plays an Ally, that Hero loses 1hp."
Does the horcrux effect come into play before my character's special ability? In other words, is my character stunned or do I survive this with 1hp? We are thinking that I am stunned.