Sentinel
Source: Player's Handbook
You have mastered techniques to take advantage of every drop in any enemy's guard, gaining the following benefits.
- When you hit a creature with an opportunity attack, the creature's speed becomes 0 for the rest of the turn.
- Creatures provoke opportunity attacks from you even if they take the Disengage action before leaving your reach.
- When a creature makes an attack against a target other than you (and that target doesn't have this feat), you can use your reaction to make a melee weapon attack against the attacking creature.