Godsteel Worldcarver (Patreon)

Weapon (a greatsword or longsword), legendary (requires attunement)

This hefty blade becomes miraculously nimble in hand, as if a portion of its weight were displaced elsewhere. If the weapon is a greatsword, Small creatures don't make attack rolls with disadvantage using this weapon as a result of its heavy property. You gain a +2 bonus to attack and damage rolls made with this magic weapon, which deals an extra 1d8 radiant damage to any target it hits.

While holding the weapon, you can use a bonus action to magically store it in a special extradimensional space. While the weapon is stored in this space, you can use a bonus action to magically retrieve it again, causing the weapon to reappear in your hand. If the sword is ever more than 30 feet away from you, it magically vanishes into the space on its own.

When you roll a 20 on an attack roll made with this weapon, you can force the target to make a DC 17 Charisma saving throw. On a failed save, the target takes an extra 3d8 radiant damage, and if the target is a creature, it is incapacitated and banished to a special demiplane until the start of your next turn, at which point the target reappears in the space it left or in the nearest unoccupied space if that space is occupied. On a successful save, the target takes half as much radiant damage and isn't incapacitated or transported. If you are a cleric or paladin, you and each creature of your choice within 30 feet of you regains a number of hit points equal to half the radiant damage dealt in this way.

The blade forged by deities when the world was made. With it, even a mortal could peek behind the curtain of the multiverse. What was this plane of existence? Was it real, or was it simply a room of a larger cosmic dollhouse?