Hoping to get some Mk3 clarification here. This question has been asked (and answered!) previously, but not to my knowledge in Mk3. So:
Would Friendly damage that doesn't originate via an attack (Kodiak Vent Steam, Conquest Creeping Barrage, etc.) trigger Vlad2's Might of Kings. My argument, and also how the question was answered in Mk2, is that although these models are Friendly, the damage did not originate from an actual attack, therefore is a legal trigger for Might of Kings.