How to deal with Irminsul

So things are going well for Kailasa. Our pretender is The Destroyer of Worlds, with A2 D5 N5. A phalanx of armored gorillas retreats towards the back of the line as the arrow bait. Sacred generals, armed with terror-casting masks and panic-casting banners spam the battlefield with morale damage, while hordes of awe protected sacred naked men dance in from the flanks and crush the enemy. Back in the citadel, I have a lot of mages tirelessly researching and manufacturing weapons for my naked generals.Mictlan is dominion killed, but then TirNaNog wants a war over the capital ruins, so I give them one. Within 3 months I'm sieging their capital. I storm the gates, fill their castle with monkeys and sacreds, obliterate their army. But then I get to Irminsul. The ugly stump has covered itself with layers of protection: liquid body so I can't cut it, resistance so my frost brands do next to nothing, and to top it off it regens 50 hits every round. It turns my army to ashes with shockwave, but lightning barely tickles my Destroyer of Worlds. He is armed with 3 frostbrands and a vine shield. They go toe-to-stump until my DOW gives up and flees. I should have gone for the dominion-kill.So, in dealing with him, I chose not to do a dominion kill. It was too late for that. I wanted vengeance.Look at that stupid look on that stupid stump face.Next game, I'm rolling an Irminsul.