Aspect of Explosive Verve is a Rogue Utility Aspect that can be found by completing the Derelict Lodge Dungeon as well as from random enemy drops. After clearing the Dungeon for the first time the Aspect will be available in your Codex of Power.
How to Obtain - Codex of Power - Derelict Lodge
Aspect of Explosive Verve Mechanics
Legendary Aspects can change the way skills and builds work in significant ways.