Chief Assassin

Silent Step: When moving in stealth, no one can find the Chief Assassin

Master Assassin: The Chief Assassin outshines all rogues in stealth. He can also find hidden characters with ease.

Sneak Attack: If the Chief Assassin has successfully vanished from sight, he can make a quick attack with his dagger, and then become visible again.

Dual Attack: If the d20 roll exceeds 15, the Chief can add a dagger swipe at the enemy, rolling the d20 again to hit.

Longsword: Melee Weapon Attack: + 5 to hit, reach 8 ft.  1 target. Hit: 1d8 + 5 slashing damage. 

Dagger: Melee Weapon Attack: + 2 to hit, reach 3 ft. 1 target. Hit: 1d4 + 2 piercing damage.

Throwing Knives: Ranged Weapon Attack: + 3 to hit, range 10 ft., 2 targets. Hit: 1d6 + 4 piercing damage.

The Chief Assassin can use his bonus action to attack a second enemy in a 5 ft range with his dagger. 

OR

The Chief Assassin can use his bonus action to vanish from the enemies sight, by performing a DC Stealth (Dexterity) Check higher than the opponents Perception. Upon success, he is no longer visible to the enemy. There are a few conditions: He must be in dim light or darker, and he must back away somewhere where the opponents cannot bump into him.