Wave 11 is one of the most difficult waves i have come across without guideance. This level contains several Ghosts and Cultists so you need magic and non--magic to win. Use at least lvl 4 Wood Elf Warriors with at least lvl 1 Human Archers with the longbow upgrade. Keep on the battlefield as much as possible but while also keeping track of your own health. I do reccommend that you get 3/4 Bannermen so you always have some money left over. Kill the mummies by either swarming Wood Elf Warriors , or going toe to toe combat with a shield. In conclusion, keep the enemy busy while your Elves finish them off.