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I think it was ruled that heroes have to be in play to be healed...but don't quote me on that...
I'm about 99% sure it was ruled that the discard your whole deck then heal your heroes strategy with The Gates of Hell was ruled that it worked... I know at one of Bryon's tournaments it happened, not sure if that's his ruling but he didn't oppose (I also don't think he saw, but still).
I think it could work, until the healing rule change comes through. It's very interesting for sure.
So what IS the rule?