these are Peak tiles, though. You’ll only be able to use Shove to push a unit in one space before you find yourself not being able to make any progress. Anyone can move through a Mountain tile, albeit slowly, but Brigands and Berserkers are the only ones who can traverse Peak tiles(and fliers too). If Bone doesn’t spawn as a flying unit or a Brigand, or if any of your units can’t take on Bone if they can even reach him, you’re kinda stuck and your only option is to restart the chapter and hope you get lucky. In a future update, there should be an option to force Bone to stay a Brigand even if everything else is randomized.