I know there is already a reaper lore, but I don’t much like it.
Seeing as certain beasts have innate magic capabilities, magic is natural. It is a part of the natural order. That is, normal magic. Dark magic is by no means natural.
No beasts can raise the dead, or kill someone and turn them into an undead minion. Only dark lords, the wizards who practice magic that deals with necrotic power, do.
Whenever a dark lord is blooded (kills their first victim using dark magic), a reaper is formed. Some scholars believe it is nature crying out to end the unnaturalness of dark magic. The reaper’s sole goal is to kill the dark lord that caused the reaper to come into existence.
The reaper will do anything to kill their arch nemesis. Because dark lords usually learn some type of life-prolonging magic, and can raise armies to defend themselves, a reaper must be patient - it may be centuries before an opportunity presents itself. Once the reaper is successful in destroying their nemesis, they will end their own lives, because reaper’s use dark magic themselves to help in their goal. They would be hypocrites if they used dark magic to catch the dark lord, and didn’t punish themselves.
One dark lord was a noble of a kingdom near adiart, whose name has been forgotten, both his and his castle’s. This is because he used his magic to kill almost the entire population of his kingdom, and then turn the rest into zombies bound to the dark one. Afterwards, he cast a memory alteration spell - making every living thing in a thousand mile radius except himself forget about him and the lost kingdom. Of course, his reaper was far from living…
Realizing that the zombies would not serve as protection enough against his reaper, he would need to distract it long enough to come up with an army to fend off the reaper.
Every month it seemed, castle adiart was sending out scouts to find information to add to it’s archives. It was only a matter of time before they remembered his forgotten kingdom.
One of the thousands of known dark spells is soul crux. The user scratches into a stone floor a star, then spills the blood of 9 black kittens in the middle. Around the edge, the magician places an object that used to be the possession of each of the intended targets of the spell. The dark one then speaks their names. The victims of the spell suffer terrible headaches and nightmares for the rest of their lives. All of their children will also be affected by the spell, and their children’s children, and so on. In addition, if the magician is murdered before all the victims of the spell are dead (and his murderer is not one the victims), then the dark lord shall inhabit the body of his killer, and everyone affected by the spell shall die.
This dark lord cast soul crux on the inhabitants of castle adiart.
A reaper is aware of every spell their dark nemesis casts. A reaper will go to any length to kill their dark enemy. By any means necessary, the unnaturalness of their magic shall not persist, the reaper believes.
This particular reaper couldn’t kill his nemesis until all of castle adiart was dead.
The dark lord looked forward to either being able to stop worrying about adiart’s scouts, or being able to forget his undead adversary.