Ankhseram Black Magic

Death Magic is a black Magic utilized by Zeref. Zeref has the ability to cause any living thing around him to die when he uses Magic. The name of said Magic is unknown. This Magic seems to burst at random times but he can tell when it is going to happen, so this gives people a chance to escape. Certain things can protect people from the wizard's blast such as Natsu's scarf saving himself, Evergreen, and Elfman. It is implied that the Magic activates whenever he is agitated, scared, or surprised. Zeref involuntarily releases a wave of Death Magic and anything hit by it dies. Like the rest of his Death Magic, he has no control over it.