Broken Hero Sword

The Broken Hero Sword is a high-tier Hardmode material, and cannot be used by itself offensively. The Broken Hero Sword has a 1 in 250 chance of dropping from either a Frankenstein or Swamp Thing during a Solar Eclipse, which can only happen in a Hardmode world.

Trivia

 * This item may be an allusion to the classic literary trope of the disgraced or defeated hero who must repair their sword.
 * It may also be an allusion to the similar trope of taking up the weapon of a past hero (perhaps killed by the monster dropping this item) to fulfill a destiny.
 * Building on this, it might be a reference to the Shards of Narsil, the sword which severed the One Ring from Sauron's hand in the popular book series/movie series The Lord of the Rings.
 * Given that Terraria has other instances where Link from Legend of Zelda is referred to as 'hero' this probably is a specific reference to the Broken Goron Sword from Ocarina of Time.
 * This item may be a reference to the sword that Riven from League of Legends carries, which shares a similar shape.

History
It could also be a nod to games such as secret of mana in which the hero finds a rusty broken sword and has to have it forged into its true form.