The Four Stones Ritual

Graveyards are home of those who’ve passed, but sometimes infested with undead, mostly due to a necromancer summoning zombies or other undead, or an artifact unleashes a power that brings the dead back to life. Priests, druids, and other spellcasters have developed several methods to keep the undead in their graves, one being the Four Stones Ritual.
Druids first developed the Four Stones Ritual in 31AT during a zombie outbreak in eastern Pinegaard. For this ritual, the druids used four different colored stones to represent four elements - fire, water, earth, and wind. Each stone was imbued with the elemental energy it represented and placed them in the center of a graveyard. Once the druid conducting the ceremony channeled enough energy into the stones, they unleashed a power that destroyed the zombies.
For the ritual to work, the person conducting the ceremony has to place the four stones in the center of the graveyard, crypt, or other area where dead bodies are present.
Once the stones are placed, they channel the elements and nature, bringing that energy into the stones, and unleashing it in a multi-colored blast that incinerates all undead within a one-hundred mile radius. Besides destroying undead, the energy covers the ground in a magical barrier, preventing the undead from coming out of the ground.
The one drawback about the ritual is that it only works on weak undead like zombies or animated skeletons. Powerful undead, such as a lich or a vampire not only can withstand the energy black, but they can also break through the barrier if they focus their power on breaking the stones.
The ritual’s one weakness is the stones. If the stones are chipped or broken before the ceremony begins, the ritual won’t work.
Druids are researching other potential element they could channel into stones for the ritual. Some have even tried using blood magic.