Gruesome Combatant (5e Feat)
From D&D Wiki
Prerequisites: Strength or Charisma score of 15 or higher
You use your skills in combat to put fear into the hearts of those that oppose you.
- Increase either your Strength or Charisma by 1
- When you score a critical hit on an attack against a target, you may use a bonus action to attempt to frighten all enemies within 15 feet that can see you. Enemies who reach these requirements must make a WIS save (DC 8 + your proficiency bonus + the ability score increased). Upon a failure they become frightened for 1 minute. The frightened targets can attempt this saving throw at the end of their turns, ending the effect on a success.