Ambusher

You have mastered getting the drop on your enemies. You gain the following benefits:

• Increase your Dexterity or Intelligence by 1, to a maximum of 20.
• Whenever you roll initiative, and are hidden from at least one creature that isn't friendly to you, you can add your proficiency bonus to the roll.
• When you take your first turn in combat, and you are hidden, you can attempt to ambush (no action required). Choose one creature you are hidden from that is not friendly to you - that creature must succeed on a Wisdom saving throw (the DC equal to 8 + your proficiency bonus + the ability modifier of the score increased by this feat). On a failure, that creature is Frightened of you for 1 minute. A frightened creature can repeat its saving throw at the end of each of its turns, ending the effect on a success.