nightmare killers

Born from the nightmare spots that from within the sea of dreams nightmare killer rouges are gifted with the ability to adopt the traumatic, illusory visage of peoples nightmares and use it to paralyze their opponents with fear before striking the killing blow. Many assassins and criminals within the sea of dreams adopt these abilities to greatly enhance their power to kill on the behalf of their masters.

nightmare visage

 Starting at 3rd level when you this subclass as a bonus action on your turn you can assume the look of a nightmarish creature of your design for 10 minutes or until you are unconscious. Whilst you are in your nightmare visage you are resistant to psychic damage and cannot be effected by spells that magically influence your nature or personality, e.g. calm emotions or sleep. you can appear one size larger or smaller than your current size and can also produce a dim light reaching 20ft. when you enter your nightmare visage each creature within 120ft of you that can see you has to make to make a wisdom saving throw equal to 8+ your dexterity modifier +2 or be afraid of you for 2 hours. 

strike with fear

Also at 3rd level you gain advantage on rolls to hit a creatures who are currently afraid of you. 

evolved nightmare

At 9th level when you go into your nightmare visage you now gain a flying and swimming speed equal to your walking speed and you can now see through any magical darkness with any dark vision you have whilst in this form. You now also gain temporary hit points equal to double your character level and only your enemies now need to make the saving throw when you enter your nightmare visage. 

manifest nightmare's

at 13th level you can now use a bonus action whilst in your nightmare guise to manifest any martial or simple light weapon in your hand(s). The weapon lasts for as long as your nightmare guise and is destroyed when it ends. The weapon deals necrotic damage instead of its original damage type. 

nightmare incarnate

At 17th level when you enter your nightmare guise it now makes your enemies afraid of without any saving throw when you enter it. You can now also ,with your manifest nightmare feature, now manifest any marital or heavy weapon instead of just light weapons. You can now also create a nightmarish duplicate of yourself to fight alongside you. The duplicate has the exact same stat block as you but all its attacks deal necrotic damage and it can only take the attack or help action as an action on its turn. It can also take any bonus actions you would have access to but can't take reactions.