Assassinate

3rd-level Assassin feature

You are at your deadliest when you get the drop on your enemies. You gain an additional way to use your Sneak Attack; you don’t need Advantage on the attack roll to use your Sneak Attack against a Surprised. When you deal Sneak Attack damage in this way, you may choose to deal maximum damage, rather than rolling.

You may do so a number of times equal to your proficiency bonus, and regain all expended uses after you finish a Long Rest.

Hidden Blade

6th-level Assassin feature

As a Bonus Action on your turn you can become Invisible until the end of your next turn. Once you use this feature, you can’t use it again until you finish a Short or Long Rest.

Debilitating Strike

10th-level Assassin feature

When you force a creature to make a saving throw against one of your Subtle Strike options, the target makes it with Disadvantage.

Death Blow

14th-level Assassin feature

You become a true master of instant death. When you deal Sneak Attack damage to a Surprised creature, the target must make a Constitution saving throw with a DC of 8 + your Dexterity modifier + your proficiency bonus. On a success, you deal maximum damage with the attack. On a failure, the target is reduced to 0 hit points, and dies.

You may use this ability once, and regain the ability to do so after you finish a Long Rest.