Daughters of Satan.

Tarnsai has the power of water, Plerngpit has the power of fire, Eurngsai has the power of earth/soil, and Wayuta has the power of wind. They found an old book in a cave when they were in the forest for a class fieldtrip. After they found it, they were in the process to learn how to use their powers. They accidently learned it through the dark forces with a dark master who taught them.