The item was created by Shar for a disciple of hers long ago, but eventually the item was lost. 

The rapier seems to have dark, negative energy that sucks out the light in the surrounding area. The sword gives the unattuned carrier small urges throughout the day to seek out darkness. The more you stare at the sword the more you get the alarming & peaceful feeling of forgetting .

How to attune to the item:

• Either at night or a dark room, meditate with the rapier in your hands, in silent reverence to Shar for 4 hours.

How to break attunement with the item:

• Break physical contact with the sword (If the item is sheathed, this will still count as physical contact)
• Store the sword in the backpack.

When attuned: 

• +8 to attacks
• +8 to damage with necrotic damage
• Two charges of level 1 sleep spells per a long rest. 
• The Rapier of Shar will attempt daily (*DM to role D20 + D4 to find out when) to take complete control of the wearer.

  How it works:

  1. The wielder must make a Charisma saving throw, with a DC equal to 12 + the item's Charisma modifier (which for this weapon is a 4)
  2. While charmed, the wielder must try to follow the item's commands (which are listed below). If the attuned wielder takes damage, it can repeat the saving throw, ending the effect on a successful save. Whether the attempt to control its user succeeds or fails, the Rapier of Shar cannot use this power again until the next dawn.

  On a successful save:

  1. You seem to come out of an intense daydream or something...you feel a general frustration coming from the rapier.

  On a failed save:

  1. User will role a 1d20
     • 1-10: Forget all, besides the following: Find darkness (in terms of lighting). If you know where the underdark or shadow plane entrance is, immediately travel to the closest one and enter. Remain in the darkness, and travel throughout the darkness to lose yourself in it. Defend yourself if attacked, but lose yourself in the journey through the darkness.
     • 11-20: Forget all, besides the following: Find any creatures who may be weaker than you and take their valuables by any means necessary. To make room you will discard anything that is not as valuable as plunder that is being taken. Continue searching out plunder. The greater the anguish that you perceive someone might have by losing their valuables the more you desire to take it from them. 
  2. User will role a 1d12
     • The user will be charmed by the Rapier of Shar for 1d12 hours.
  3. When you come out from being charmed you have no remembrance of what has transpired for the duration of the period of time. 

   

When not attuned:

• The rapier requires to be worn by the wearer at all times/with attunement in order for any of its properties to be used.
• Disadvantage on each attack
• It will be unwieldy, and each attack attempted will have disadvantage. 

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

Notes: Bonus: Magic, Stacking Bonus: Charisma Score, Meditate in the night or a dark room for 4 hours in quiet prayer to Shar., Finesse, Vex