Most people can acknowledge that they will one day die, but they still want to be remembered well in death and have their stories told through the ages. You can play with this particular concept by using undead as a projection of humanities existential fears. Let’s have some fun 🙂
The fear of the Unknown
Unlike reality the presence of divine forces is readily apparent through planar travel, divine magic, and celestial creatures. There is no ‘fear’ of what happens after death since you can travel there yourself, use speak with dead, or just resurrect them. However, what if it wasn’t so simple? If it wasn’t uncommon for souls to get lost in transition it could be one ‘natural’ method for undead to occur in the world. It could also be VERY creepy!
You could cause undead to say unsettling things that cause them to fear where their souls may go to. A zombie screaming ‘I’m on fire!’ as it rushes the heroes not because it is physically on fire, but because their soul made a wrong turn and is being burned in Avernus and it feels this pain. You could also have an undead fight for its ‘life’ begging the players to let it go because it has seen what lies in the shadows of death and it terrifies the creature. Keep in mind that being undead is rather unpleasant. They often have to eat the flesh of the living to maintain their existence. If they are willing to murder hundreds of their kin to prevent falling back into death what IS waiting on the other side?
The fear of Dying
Sometimes it is not what happens after death that terrifies the players, but it is the process of dying that haunts them. You can easily use undead to portray horrific manners of dying to remind the heroes of their mortality and to stoke the fear that maybe their pain will echo into eternity too.
I love having undead with terrible wounds blaming the adventurers for their death. For example, having a ghoul that clearly once was a dwarf who died when acid ate his face yelling ‘what have you done to my face! She won’t love me now!’ before attacking eludes to an older and sadder story. Or a zombie covered in burn marks since she was burned at the stake clawing at the heroes to ‘put her out’ even though she isn’t presently on fire, but it is clear she still feels its flames.
The fear of Being Forgotten
This one is my personal favorite. Most people want to be remembered well and have a packed funeral filled with crying loved ones. You can play on the fear of being forgotten in some lovely ways.
Having a skeleton using his finger to etch ‘my name is’ over and over on the wall before turning to the players and saying ‘I can’t remember my name. TELL ME WHO I AM! WHY WONT YOU TELL ME?!’ evokes not just horror but tragedy of a lost identity. You can also twist their previous identity to add a different flavor. A person that once was a loved teacher, could become a child eating ghoul because they don’t remember much about their past life except that they ‘loved children.’