User blog comment:Tommy,Klaus&Kol2012+/How to Kill a Levithan/@comment-3481504-20120225013757

The Colt wouldn't work, they'd just heal from being ripped apart, destroying their vessel wouldn't kill the actual Leviathan. A reaper most likely couldn't kill one, nor could a pagan.

Here's the only possibilities that could permanently destroy them: God, Death, and the Archangels.

Seraphs and Pestilence, War and Famine could probably severely injury them.