Let's ham up the Dracula impression!
The first stage in this video is actually a really good grinding stage because of the invincibility. I chose to just dispose of the effect and handle the stage normally, but you can juggle the Geo Block such that you're invincible on the enemy turns, and remove it on your turns to deal damage, or just leave it, throw all or most of the enemies together and put them on the one square with no effect and have a low level character kill them with no risk. Just make sure the defences aren't so high that you can't do any damage to it any more.
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