Blade Barrier

Prerequisite: proficiency with twinblades
Your expertise with twinblades allows you to turn your defensive flourish into an offensive strike. When you use the Whirl special bonus action with a twinblade, you gain the following features:

• You can make one additional melee attack with the weapon. This attack uses the same ability modifier as the primary attack, and the weapon’s damage die for this attack is a d4.
• Until the start of your next turn, other creatures provoke an opportunity attack from you when they enter your reach or make a melee attack against you while within your reach.