The Twisted Sword

The Twisted Sword is a Legendary sword in Diablo III, added in patch 2.4.0 (though it was present in game files since patch 2.1). It requires character level 70 to drop.

The unique affix boosts each Energy Twister proportionally to how many Twisters are summoned at any given moment, up to a maximum of 5 at a time (which equals up to 750% extra damage of each).

As of patch 2.6.10, it also adds the Raging Storm rune effect (without changing the Elemental Damage type) to any other, allowing up to 5 Twisters to merge into one.

Development
When this item was added to the game, it did not have the limit on how many times its effect may stack, leading it to be severely overpowered. The item was nerfed to only allow a maximum of 8 stacks, but due to a bug, this limit did not apply. Even after a fix, it still proved to be overpowered, leading to the eventual limit of 5 stacks as of patch 2.4.2.

Originally, this sword was named Nazim's Greatness. Its description would read as follows: