Blackout

At Level 1 with a patron, or at level 3 as a sorcerer or wizard, you have been around spirits long enough to witness conjurations, dead reanimating and so on. This has allowed you to call on the darkest part of your soul (if you are warlock then whatever/whoever your patron is will be called upon and it can not be used in an open space) and the entire enclosed area becomes pitch black as you teleport behind the creature. During the darkness, the creature will be frightened, blinded and will take disadvantage on attack rolls. This spell ends after one round or can be interrupted before casting by upsetting the casters concentration. Spell can be used once per day.