Blessing of Orcus

Description (Slinger)
This item has been blessed by Orcus, the Roman minor god of death, related to the main Roman god of death, Mors. As such, this firearm is now bound to your soul and is indestructible by any means except for reality-overwriting abilities and the will of gods greater than him. Most are.

Reference
Chapter 59 "To The Couple Goes The Spoils"