Assassination

Epic Boon Feat (prerequisite proficiency in stealth)

You have been trained to end fights before they begin by mastering the art of assassination.

If the target is facing away, otherwise engaged, or unable to see the attack coming (dm discretion) then the attacker has advantage and the target has disadvantage. The attacker will roll a stealth check with advantage and add any relevant modifiers while the target rolls perception with disadvantage. On a pass, the attacker rolls to hit with advantage. On a hit the target takes double damage and takes triple damage on a nat 20. If the hit misses then the target has one reaction attack.