Furnace Ferno Astrid Bauble vs Viperia Cobressa Emily Krexx.
Viper Krexx die round one. Cobra is invincible, Wildfire does not spread to her.
Krexx is revived, Cobra becomes invincible again. Ferno targets her with Wildfire, amplified by Fired Up, she takes zero damage x2, Wildfire does NOT remove invincibility.
Does first attack only give a *chance* to apply wildfire? Because if it's supposed to [apart from protected heroes], then this is a bug.
edit: description does indeed say, "chance" to apply Wildfire. I didn't know that because it always gets applied to my heroes.