Immortality Negation

Immortality Negation is a specific application of Power Nullification in which one is able to bypass the immortality of a being, thus allowing them to kill an Immortal being.

Immortality Negation can take on many forms, such as through the disabling of regenerative capabilities, the destruction of the soul, or various other possible ways in which it can manifest.

It would be a No Limits Fallacy to assume that such a power can kill any being, it is to be assumed that any negation power has its limitations based on the strongest thing it has nullified, and a character may be resistant to the ability (at least in one of its forms), preventing it from having its usual effects.