Assassin's Hidden Blade

You have a +1 bonus to attack and damage rolls made with this magic weapon. 

This dagger of artisan craftsmanship has a mechanism that controls a retractable blade with a flick of the wrist. It is comprised of a metal spine and frame that is attached to a protective fitted sleeve fitted to the user's forearms, while strapped this way it looks like a mundane bracer. It deals 2d6 damage on a successful hit, also as a free action the wielder can have the blade extend from its sheath. When attacking a surprised creature, you can add 1d8 to the weapon's damage roll. 

Hidden Latch: The gauntlet holding the blade has a small latch hidden in the wrist small enough to be undetected but large enough for 3 extra viles of poison.

Undetectable: This weapon is inconspicuous and out of the way allowing it to be snuck into no weapon zones incredibly easily. A DC20 investigation check by a person to even tell that it is not a normal bracer.

You must spend a long rest adjusting the fitting to fit the specific arm and muscle density to become attuned. 

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

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

Notes: Assassins Born and Raised, Finesse, Light, Vex