Legendary items are unique weapons and accessories that are exclusive to Malice Mode. They are very powerful for the point at which they can be obtained, and the weapons often have a secondary right-click attack. They drop from their respective bosses with a 100% chance.
Prior to the 1.2.1.001 update, the weapons' damage scaled as you progressed further into the game, and their abilities became upgraded upon defeating their respective boss. They also had a very small chance of being dropped by any enemy, with increased chances to drop from the bosses which are now their exclusive source. These features have since been removed from the weapons due to balancing issues, however The Community still retains similar scaling features.
Prior to the 1.3.2.001 update, the drop rate of these items was 10% instead of 1%. However, they were significantly weaker as a result.