Blackguard's Shortsword 2014
Weapon, common
You have advantage on attack rolls made with this weapon against a target if another enemy of the target is within 5 feet of it, and it has no allies within 5 feet of it.
Properties
Finesse
When making an attack with a finesse weapon, you use your choice of your Strength or Dexterity modifier for the attack and damage rolls. You must use the same modifier for both rolls.
Light
A light weapon is small and easy to handle, making it ideal for use when fighting with two weapons.
Source: Vault of Magic (Kobold Press) · License: OPEN GAME LICENSE Version 1.0a details