Ghost Faced Killer

Long ago, a persecuted clan of dangerous warriors sought a way to take revenge against their oppressors. Through sorcery, the spellcasters of the clan beseeched dark spirits to reveal a way that their clan might survive the coming strife and take revenge on the emperor who sought to crush them. The clan members struck a dark bargain, and the demon-spirits they had contacted provided the clan with a means to the bloody ends they desired. Donning terrifying masks to hide their identities, warriors of the clan crept into the imperial palace, and through the evil power of the pact they had made, passed invisibly and intangibly into the imperial household and murdered the entire imperial family, plunging the country into bloody civil war once again. No one ever discovered the clan?s honorless actions, and to this day, no one knows what clan the ghost-faced killers came from.

Today ghost-faced killers act as assassins and spies for hire, a mercenary clan that hides behind a guise of open and honorable conduct. When on a mission, they wear porcelain demon-masks of ghostly white to hide their identities and as a symbol of the pact their clan made with the demon-spirits. Through training and discipline, ghost-faced killers learn the deadliest and most terrifying ways to attack foes, and through their mystic connection with spirits, ghost-faced killers learn to turn invisible, walk through walls, and even see with the eyes of the spirits themselves.

Mind Games

Your presence and clan's reputation are terrifying. When you make an intimidate roll, any enemy that succumbs to your intimidation will have disadvantage on initiative rolls for 1 min. Enemies under this effect are considered surprised on the first round of combat, though they may act when it is their turn. 

Murder

Starting at 3rd level, you are at your deadliest when you have gotten into your enemies head. You have advantage on attack rolls against any creature that hasn’t taken a turn in the combat yet. In addition, any hit you score against a creature that is surprised is a critical hit.

One with the Spirits, Ghost Step and Ghost Sight

Starting at 9th level, your pact with spirits have granted you the ability to cast Invisibility and See Invisibility. Once you have done so, you cannot do so again until you finish a short rest. At 13th level, you may cast True Seeing, and at 15th level, you may cast Etherealness. Once you do so, you can't do so again until you finish a long rest.

Frightening Slaughter

Whenever you kill an target with a sneak attack using a melee weapon, you may use your reaction to have enemies within 30ft that witness the event make a Wisdom saving throw, DC 8 + proficiency bonus + Cha modifier or be frightened of you for rounds equal to your proficiency bonus. Once you have used this ability, you can't do so again until you have finished a long rest. You gain an additional use of this ability at level 8, and again at level 14.

Frightful Cleave

At 13th level, you gain the ability to make great use of your frightening slaughter. You have advantage on attack rolls against creatures frightened of you. Additionally, whenever you fell a creature that is frightened of you, you may use your bonus action to move up to your movement and make another attack against a foe. 

Death Strike

Starting at 17th level, you become a master of instant death. When you attack and hit a creature that is surprised, it must make a Constitution saving throw (DC 8 + your Charisma modifier + your proficiency bonus). On a failed save, double the damage of your attack against the creature. Additionally, enemies that witness this event will have disadvantage on their saving throw against your Frightful Slaughter ability.