Black Hole (Patreon)

Weapon (longsword or rapier), legendary (requires attunement)

This black longsword has a pulsating, cosmic void at its center. The void is a tiny shred of a sphere of annihilation, which only functions to grant this weapon its various properties.

You gain a +3 bonus to attack and damage rolls made with this magic weapon, which has the finesse property. While holding it, ranged attacks against you are made with disadvantage. Whenever a ranged attack misses you while holding the longsword, you gain 2d6 temporary hit points, and the missile or spell permanently disappears into the void at the weapon's center. If the missile is a magic item, it immediately reappears in a random location within 1,000 feet of you. The first target you hit with the sword on each of your turns takes an extra 2d10 force damage.

While holding the longsword, you can use a bonus action to magically split it into two rapiers named gravity and mass, which each have the light property. The void vanishes when the longsword is split. You gain a +1 bonus to attack and damage rolls made with these weapons, instead of +3. If you're proficient with longswords, you are proficient with these rapiers. Each sword has its own unique properties.

Gravity. Gravity has an elaborate, twisting basket at the base of its blade. When you hit a creature with this weapon, the target's speed is reduced by a cumulative 10 feet until the start of your next turn. A creature whose speed is reduced to 0 in this way must immediately succeed on a DC 16 Constitution saving throw or be magically restrained until the start of your next turn.

Mass. Mass has a hefty, armored guard around its handle. A creature hit with this weapon for the first time on a turn must succeed on a DC 16 Constitution saving throw or feel a powerful, invisible weight thrust upon it; such a creature has disadvantage on ability checks, saving throws, and attack rolls it makes using Strength until the start of your next turn.

A creature not attuned to black hole can still benefit from the rapiers' properties. Such a creature must make a DC 16 Strength saving throw at the end of each of its turns while holding either of the rapiers; on a failure, the creature drops them to the ground at its feet.

Fusion. While holding either gravity or mass, you can use a bonus action to cause the other one to fly to the hand holding the weapon. To do so, you must be attuned to black hole, and the other weapon must be within 60 feet of you. If another creature is holding the other rapier, it must be willing to let the weapon go. When the two weapons are reunited in this way, they recombine into black hole.

Immediately after black hole is reformed in this way, you can use an action on the same turn to cause a brief tear in spacetime to form. Any creature of your choice that you can see within 120 feet of you must make a DC 16 Strength saving throw. On a failed save, a creature is pulled up to 40 feet toward you and takes 4d10 force damage. On a successful save, a creature is pulled half as far and takes half as much force damage. Once this action has been used, it can't be used again until the next dawn.

The end lies at the beginning, and the beginning at its end.