Whirling Shortsword

These magic weapons were forged with lightweight metals and designed for speed rather than brute force. Whirling weapons have the finesse and light properties and whistle softly when swung through the air. When you take the Attack action and attack with a whirling weapon that you're holding in one hand, you can use a bonus action to make another attack with the same weapon. You don't add your ability modifier to the damage of the bonus attack, unless that modifier is negative. If you're holding a different whirling weapon in each hand and engage in two-weapon fighting, you can make one attack with each weapon when you use a bonus action in this way. In addition, if you have the Two-Weapon Fighting fighting style, you can add your ability modifier to the damage of the bonus attacks.

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.

Proficiency: martial, shortsword Source: The Griffon's Saddlebag: Book Two p. 188 (Third Party), Player's Handbook (2014) p. 149