Hand of Vengeance

 is a unique companion perk in Fallout: New Vegas.

It is acquired by completing Heartache by the Number, Rose of Sharon Cassidy's companion quest the violent way. This is done by killing Alice McLafferty and Gloria Van Graff instead of obtaining evidence against them in order to have the NCR justice system deal with them.

Effects
Rose of Sharon Cassidy gains 15% more damage with Guns.