God Slayer Magic (滅神魔法, Metsujin Mahō) is a Caster-Type Ancient Spell used by God Slayers; it is part of the Slayer Line. God Slayers, like Dragon Slayers, have the ability to eat their own element; doing so rejuvenates them. However, unlike Dragon Slayers, no matter what element the God Slayer uses, it is black in colour. In addition, the Magic that God Slayers use is, in general, superior to that of Dragon Slayers.
God Slayer Magic is a form of Ancient Spell in which the caster is able to attain the abilities of a "God", using a specific element as their type; or so it would seem. The basis of every Ancient Spell in the Slayer Line is that 'to defeat your enemy, you must take upon the traits of your enemy', but for God Slayer Magic, this is drastically different; but it is unknown how. God Slayer Magic enables its users to transform their physical bodies into an unidentified being. As a result, the user can transform their body with features of their respective element, utilizing both offensive and defensive styles. The certain elemental type of God Slayer Magic can be conjured from the caster's body and be used for various purposes, mainly in combat. In addition, the colour of each God Slayer's element has a black tint, regardless of what it may be. They can consume external sources of their respective natural element to replenish their own energy. A God Slayer is immune to the effects of their own element, and can consume external sources of their element to replenish their strength. However, a God Slayer cannot consume the element that they produce themselves, and elements must be consumed through the mouth. However, it appears that they cannot eat their own "God-like" element and instead one of a lower level. It is not vice-versa with Dragon Slayers, however, unless the Dragon Slayer has emptied out their own Magic Power to create a vessel for the respective element. Although it is unknown how one actually learns God Slayer Magic aside from the theory above, which most subscribe to, one such occasion allowed Chelia Blendy to learn it from a book; and it is theorized that she learnt the magic from one of the grimoires.