Super Counter (5e Feat)

Prerequisites: Dexterity 13 or higher.
You are a specialist in countering attacks. You gain the following benefits:

You can choose to let a creature make an attack with advantage against you. If the attack hits you, you can use your reaction to make an attack with advantage against this creature. On a hit, roll the damage die, and subtract the amount from the damage you would've taken. The creature with the lowest result on the damage roll takes the remaining damage.

You can use your bonus action to choose one creature you can see within 30 feet. If that creature makes a melee attack against you before the start of your next turn, you can use your reaction to make an opportunity attack against it.