Backhand

A razor-sharp steel blade fitted to a spring-loaded mechanism on a leather bracer. An ingenious device invented with deadly intention.

This non-magical weapon is fitted on your arm rather than wielded in your hand. Thus it can be wielded and used even if you have other weapons equipped simultaneously. When you take the attack action with this magical weapon, the blade is pushed forward on a spring, making its appearance sudden and forceful. 

While attuned to it, you gain a +2 bonus to both attack and damage rolls with the weapon. While the blade can only ever be used to attack once each turn, it grants natural advantage on the attack if combat has not yet started. Also, it deals an extra 1d4 of piercing damage on any successful attack, and a successful attack on an unsuspecting target counts as an automatic critical hit.

Cannot be used while wearing other gloves or gauntlets.

Proficiency with a Dagger allows you to add your proficiency bonus to the attack roll for any attack you make with it.

Notes: Bonus: Magic, Damage: Piercing, Finesse, Light, Thrown, Nick