Ring of the Assassin Lord

Ring, legendary (requires attunement by a rogue)

This dagger-shaped ring has been worn by famous assassins throughout history. While wearing this ring, you can deal your extra Sneak Attack damage twice, instead of once, on each of your turns. The two attacks must be made against different targets, and the Sneak Attack damage for the second attack is halved.

The inside of the ring is blank when you first attune to the ring. A small tick mark appears on the band's interior whenever you reduce a creature of challenge rating 1 or higher to 0 hit points with an attack in which you dealt Sneak Attack damage. Once the ring has 50 marks, your Dexterity ability score increases by 2, as does your maximum for that score, and the ring stops adding more marks. If another creature attunes to the ring and gains this bonus, your Dexterity ability score and maximum for that score return to normal.

Virnym gazed into the empty courtyard. Well, it was mostly empty. Two guards stood watch on either side of the door to the central chambers. Duke Fentenwald, his mark, was due to be inside.

He silently drew two arrows from a quiver and nocked the first in his bow. He pulled it back, aimed, and fired. The second arrow was loosed a moment later with the same deadly efficiency as the first. His ring radiated a faint warmth and cast a dim glow from the ruby set inside.

Virnym gazed into the now truly empty courtyard to admire his work.