The Locker Key (Patreon)

Weapon (scimitar), artifact (requires attunement)

This crude-looking blade banishes unfortunate souls to the crushing depths far below the ocean surface to meet their painful end.

Dormant

The scimitar grants the following benefits in its dormant state:

You gain a +1 bonus to damage rolls made with this magic weapon.

This weapon has 3 charges and regains all charges daily at dusk.

To the Locker. When you hit a creature, you can spend a charge to have this weapon deal an additional 2d10 necrotic damage. If this damage reduces the target to below 30 hit points, the creature must make a charisma saving throw. The DC is equal to 10 + your proficiency bonus + your charisma bonus. On a failed save the creature is teleported to The Locker, a demiplane resembling a prison at the bottom of the ocean.  At the start of the creature's turns it takes 5d10 force damage from the crushing pressure of the water. If this damage reduces the target to 0 hit points, it is crushed into pulp and does not return, after which this weapon regains a charge. A creature can repeat the saving throw at the end of each of its own turns, ending the effect on itself on a success and reappearing in the space it left or in the nearest unoccupied space if that space is occupied. The soul of a creature that dies is trapped in The Locker and cannot be restored except by a wish spell.

Curse: The Pull of the Sea. This blade is cursed, and becoming attuned to it extends the curse to you. As long as you remain cursed, you cannot unattune from this weapon except by an effect such as the remove curse spell. If your attunement ends, the item returns to its dormant state as though no creatures had died from its abilities. If a humanoid creature has not been killed by the To The Locker ability within one week of the last, on each subsequent day you must roll one of your hit dice. Your hit point maximum is reduced by that amount as the blade begins to siphon your soul. Your hit point maximum is reduced this way until you kill a humanoid creature with the To The Locker feature. If your hit point maximum is reduced to zero, you die and your soul is transported and trapped in the depths of The Locker.

When 25 humanoid creatures have died using the To The Locker feature, this weapon reaches its awakened form.

Awakened

The scimitar grants the following benefits in its awakened state:

The weapon’s bonus to attack and damage rolls increases to +2.

The additional necrotic damage dealt by To The Locker increases to 3d10, and the hit point threshold is increased to 40 hit points.

Gaze into the Abyss. Your mind has been blessed by the depths in ways yet incomprehensible. If you succeed on a wisdom or charisma saving throw the creature whose ability or spell caused you to make a saving throw subtracts half your charisma modifier from the next saving throw it makes before the end of your next turn. 

When 50 humanoid creatures have died using the To The Locker feature, this weapon reaches its exalted form.

Exalted

The scimitar grants the following benefits in its exalted state:

The weapon’s bonus to attack and damage rolls increases to +3.

The additional necrotic damage dealt by To The Locker increases to 4d10 and the hit point threshold is increased to 50 hit points.

Gaze into the Abyss now causes the creature whose ability or spell caused you to make a saving throw to subtract your charisma modifier from the next saving throw it makes before the end of your next turn.

Life is Cruel. Whenever you score a critical hit against a creature, you may use the To The Locker ability against the target without expending a charge.

There are few professions that garner as much legend and superstition as seafaring, and fewer still strike fear into the hearts of men like that of the Locker; a lifeless realm with nary a hint of hope amidst the crushing terrors that haunt those consigned to the bottomless depths. Those who maintain their consciousness just enough to take in their surroundings find themselves quickly driven mad as the abyssal forces shatter their fragile minds before oblivion consumes them.