Shin Megami Tensei IV: ApocalypseEdit
Throughout the conflicts that have arisen whenever gods, demons, and angels take to the battlefield, the best any of then could do was seal one another away. However, humanity was different, in that they held the power to cut down all beings. This was made possible through the Axiom. The Axiom bestowed upon humanity the power of "Observation," which was what allowed them to influence the world, even turning mythology into reality itself. This is primarily the reason why humans are often involved in the conflicts between supernatural beings, as only humans can successfully slay gods, devils and angels.
Lucifer himself states as such during the conference of the alliance between Law, Chaos, and the Hunter Association regarding the threat of the Divine Powers. Any human who has the power to cut down a godly entity is known as a "Godslayer," though how one becomes one is unknown. So far, the only known way to become a Godslayer is to die, and then be revived by a god, as was the case of Nanashi, who was killed by the demon Adramelech, only to be revived by Dagda, who intended to use him for his own goals. Flynn was also considered to be a Godslayer, though he was referred to as "Kalki" by Krishna, who wanted to use him. He would later become one after being revived by Nanashi to become his own Godslayer, if the player had chosen to create a new universe with Dagda.