Blackened Defias Belt

The Blackened Defias Belt is a leather belt that provides a bonus to attack power. It is part of the Defias Leather armor set.

The Blackened Defias Belt was upgraded from being an uncommon item to being a rare item in Patch 2.3

Source
The Blackened Defias Belt drops off Captain Greenskin (Medium 25% - 50%) in The Deadmines.