Darksingers are, as the name implies, bards who put their unique magical skill set to sinister or shadowy use. Specialized in stealth and fear, they often ply their trade in service of dark causes and masters, though some more noble examples exist (typically in the service of clandestine organizations). As they grow in skill, they become unnerving phantoms, jangling the nerves of their enemies with music or taunts that seem to come from everywhere or nowhere.
At 3rd level you learn the tools and practices of skullduggery. You become proficient with thieves’ tools, the poisoner’s kit, and the Stealth and Sleight of Hand skills. You also become proficient with improvised weapons.
Also at 3rd level, you become especially good at veiling your presence in a variety of ways. All spells of the obscurement school count as bard spells for you.
Starting at 6th level, you learn to pepper a feeling of unease into your bolstering abilities. Whenever you use your Bardic Inspiration, you may elect to lower the die size by one step. If you do, you may select a creature within 30 feet of you to unnerve. The creature makes a Wisdom save against your spell save DC, gaining the rattled condition for one minute on a failed save. The creature can repeat the save at the end of each of its rounds, ending the effect on a success. A creature may only be affected by one instance of this effect at a time.
Also at level 6, you learn to throw off those searching for you, even as you taunt them. While you are hidden, obscured, or invisible, your voice and the sound of musical instruments you play seem to come from everywhere or nowhere in particular, imposing disadvantage on checks to locate you by sound. If you remain still while singing or playing music, you cannot be located by their sound alone.
At 14th level, you learn to emit a terrifying clamor that causes your opponents terrible distress. As an action, you may spend a use of your Bardic Inspiration to play a Dirge of Terror. Enemy creatures in a 15-foot cone must make a Wisdom save against your spell save DC or take 4d6 psychic damage, gain a level of strife and become frightened. Creatures that succeed on their Wisdom save take damage as normal, but are not frightened and do not gain levels of strife. Creatures that fail by 5 or more suffer a mild heart attack. Such a creature must make a Constitution save against your spell save DC or acquire two levels of fatigue and are stunned until the end of their next turn.