Barbaroth's Blade

 This silver rapier is said to have belonged to the notorious corsair and privateer, Commodore Nathanial Barbaroth. The blade's enchantment resists all but its true master, cursing any who would take possession of it but the legendary pirate himself.

GAMBLER'S FORTUNE
At the end of every long rest when attuned to this weapon, you may roll a d4. If you do, you gain a bonus to attack and damage rolls made with this weapon equal to the roll. However, you also take a corresponding penalty to your death saving throws. These effects persist until the end of your next long rest.

ELEMENTAL SURGE
While attuned to this weapon, you may as a bonus action speak a command phrase that causes the blade to erupt in flames, ice over, or crackle with lightning. For 1 minute, attacks made with this weapon deal an additional 1d8 fire, cold, or lightning damage. Once you activate this ability, you cannot do so again until you finish a short or long rest.

CURSE
This weapon is cursed, and becoming attuned to it extends the curse to you. Until the curse is broken with a remove curse spell or similar magic, you are unwilling to to part with the weapon, and have disadvantage on attack rolls made with other weapons.

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

Notes: Finesse, Vex