destroyer

Definition:

The term "destroyer" literally means "person who destroys."

This term is often used in the Old Testament as a general reference to anyone who destroys other people, such as an invading army.
When God sent the angel to kill all the firstborn males in Egypt, that angel was referred to as "the destroyer of the firstborn." This could be translated as "the one (or angel) who killed the firstborn males."
In the book of Revelation about the end times, Satan or some other evil spirit is called "the Destroyer." He is the "one who destroys" because his purpose is to destroy and ruin everything God created.