Beast of Butchery

You fight without mercy, making short work of your foes in their moments of weakness. You gain the following benefits:

• Increase your Charisma, Dexterity, or Strength score
  by 1, to a maximum of 20.
• You gain proficiency with the flail and whip.
• You have advantage on opportunity attacks, as well as melee attacks you make against frightened creatures.