In lighted areas, the unsheathed blade of this sword sheds darkness, creating bright light in a 15-foot radius and dim light for an additional 15 feet.

Also known as shadow tongue swords. these rare blades occur when some energy, spirit, substance or being invoking darkness and shadow as anything from active power to metaphor is incorporated into the process of enchantment which otherwise would have resulted in a flame tongue or moon touched blade - whether accidentally or by design.  they also occur, though much more rarely, when soul-searing grief or hatred from some event traumatic enough to stir the gods to pity ... or the dark ones to something worse ... touches a moon touched or flame tongue blade and darkens it.

You can use a bonus action to speak this magic blade's command word, causing flame-shaped wisps of shadow to erupt from the blade. These 'flames' shed darkness in a 40-foot radius and an equal radius of shadows (causing vision to be lightly obstructed) for 40 feet beyond that. While the sword is 'ablaze', its 'flames' of shadow spread to any target it hits. These 'flames' do no additional physical damage to the target. but they continue to 'burn' the victim on subsequent rounds, draining their life force and causing them to gain a level of exhaustion each round they are psychically 'burned'.  This effect can be resisted if the creature succeeds on a CON saving throw; and if they do so twice consecutively, the flames cease to burn them. The DC of this save is 15 the first round, and drops by -3 each round thereafter.  The blade continues to be sheathed in 'flames' of shadow until you use a bonus action to speak the command word again or until you drop or sheathe the sword.

If the wielder of a dusk touched sword also possesses a flame tongue or moon touched blade and ignites them both at the same time so that any part of their areas of light or darkness/shadow overlap, roll 1d12 and consult the following table to determine the effect:

• 1 - 2: Flame tongue's light is extinguished; shade tongue's darkness/shadow takes full effect 
• 3 - 6: Flame tongue's light is extinguished; shade tongue's area of darkness/shadow is halved
• 7 - 9: Shade tongue's darkness/shadow are dispelled; flame tongue's area of light is halved
• 10 - 11: Shade tongue's darkness/shadow is dispelled; flame tongue's light takes full effect
• 12: An area equivalent to an 80' diameter sphere centered on the point equidistant between the blades is filled with a mist of writhing, constantly flickering sparks and shadows that confound the vision of all beholders.  All within this area, including the wielder and allies, must make an INT saving throw at DC 13 or be mesmerized by the pattern and behave as if they were under the influence of a confusion spell, with the following changes: on a roll of 2-6 the creature is affected as if an Otto's Irresistible Dance spell had been cast upon them; and on a roll of 9 or 10 they are afflicted with short term madness for 1d8 rounds but are subsequently unaffected by the interplay of light and shadow in the area and can see through it as if it were illuminated by normal daylight (to all others the area is moderately obscured, acting as a lightly obscured area to them and additionally treating attacks they make or spells they cast against creatures in this area as if those creatures had half cover)

 

Proficiency with a short sword allows you to add your proficiency bonus to the attack roll for any attack you make with it.

Proficiency with a Shortsword allows you to add your proficiency bonus to the attack roll for any attack you make with it.

Notes: Exhaustion, Utility, Finesse, Light, Vex