User blog comment:Emptylord/Custom Champion - Behemoth the Earthbreaker/@comment-27802145-20170430041627/@comment-7709681-20170430221239

Same as Nasus: The only way to know is check his stacks on his mini-HUD upon clicking.

As for the damage reduction: %Damage reduction from Armor/MR has diminished return, and their calculation is individual for each, if so why not make the ability have both Armor/MR ratios to increase the ability's damage?