Final Blade (5e Feat)
From D&D Wiki
Prerequisites: Dexterity 15 or higher
You learn how to increase your enemies' injuries caused by you.
You can stow or unsheathe a weapon without spending any form of action.
At the end of the current round of initiative, you can spend your reaction to deal an amount of damage equal to the number of damage dice you dealt plus your attack's damage modifier to enemies you've attacked this round. For example if you dealt 3d6+3 turn damage to a target you deal 6 damage.