“ Magic is the lifeforce of all living creatures, and it is from it that all life is made - in areas with lots of undead, magic might actually be missing or weak, which puts a whole new spin on how dangerous the undead are. Even simple zombies can be troublesome if you're relying on mages and you hit a pocket of undead making a low-magic zone...”
“ Rather than making a baddy impossible to hit, consider giving it mega-hit points.
Super hard to hit leads to great player frustration. Allowing them to do damage leads to a sense of accomplishment. another variation of this would be to give the bad guy a forcefield that shows damage.You could also give them a mastermind ability that sluffs the damage of to minions who should be easy to kill.Once in a while a super high to hit encounter is ok ,but it should be few and far between.
Your mileage may vary”
“ One morning, the sun does not rise. It seems that a great darkness has settled across the kingdom - at first, it is merely an inconvenience, but as time passes and plants begin to sicken and die, some action must be taken. As the deluded King plans the sacrifice of fifty tender virgins in the name of the Sun God, rumours spread of an ancient barrow uncovered in the hills...”