Caves and tunnels are a second home to you.
Benefit: While underground, you receive a +2 trait bonus on initiative checks and a +1 trait bonus on weapon damage rolls for critical hits (this damage is multiplied on a critical hit).
Pathfinder Roleplaying Game: Ultimate Campaign © 2013, Paizo Publishing, LLC; Authors Jesse Benner, Ben Bruck, Jason Bulmahn, Ryan Costello, Adam Daigle, Matt Goetz, Tim Hitchcock, James Jacobs, Ryan Macklin, Colin McComb, Jason Nelson, Richard Pett, Stephen Radney-MacFarland, Patrick Renie, Sean K Reynolds, F. Wesley Schneider, James L. Sutter, Russ Taylor, Steve Townshend.