Blade of the Deep

The Blade of the Deep Weapon (longsword), rare (full power only usable if attuned)

This elegant but unsettling blade bears a hand-guard wrought in the likeness of twisting tentacles, as though frozen mid-coil around the wielder’s hand. The metal has a faint bluish sheen, and small veins of black shimmer like oil across its surface. The hilt is wrapped in deep blue leather, stained darker where saltwater has seeped in. The hand-guard’s sculpted tentacles seem almost to move when caught by shifting light, and the pommel bears a small pearl-like stone that glows faintly when submerged. When drawn, it exudes the scent of salt and cold iron.

Damage: 1d8 slashing (versatile 1d10) (counts as magical)

Weight: 3 lb.

Type: Martial weapon

Properties

once attuned, the sword adds 1 to attack and damage rolls in addition to having the following abilities:

Brine-Tinged Strike

Once per turn when you hit a creature with the Blade of the Deep, you can choose to let a trace of black brine leak from the blade to the wound. The target must succeed on a DC 13 Constitution saving throw or have its movement speed reduced by 10 ft. until the start of your next turn as the wound ed area feels water-heavy and cold. This ability can be used a number of times per long rest equal to your proficiency bonus.

Gift of the Abyss.

While attuned to the blade, you gain a swim speed equal to your walking speed, and you can breathe underwater. In addition attacking with this weapon while underwater does not incur disadvantage.