Muramasa

The Muramasa, not to be confused with the Cobalt Sword, is a glowing blue Broadsword that is only found in the Dungeon's Gold Chests. It is one of the few melee weapons that will automatically swing when holding down the attack button. This weapon is decent due to its constant swing. The best modifier it can obtain is Legendary.

The Muramasa has a slightly longer reach than the Phaseblade, and deals 19 damage with a fast attack speed. It emits a decent amount of light when used.

Tips
You can get this by fishing too.
 * It may not be the most powerful of weapons, but can be effective while running for killing Slimes, knocking back flying enemies, clearing Thorny Bushes, cutting away weeds and harvesting Plants.
 * As the Muramasa is already a very quick weapon, a good tactic is to equip a full set of Shadow armor and some Feral Claws with Bowl of Soup to give it an incredibly fast swipe speed, allowing you to cut through virtually any non hardmode enemy with ease.
 * It swings even faster than the Nights Edge, but its relatively poor knockback makes it a poor choice against most enemies if not backed up by melee speed enhancements. Some may opt to keep using the Light's Bane or Blood Butcherer.
 * It's useful against weak bosses like the Eater of Worlds, especially when combined with decent armor.
 * Its long reach is perfect for battling low flyers like the Demon Eye.

Trivia

 * Muramasa is likely named after a famous swordsmith of the same name who lived in 16th century Japan, whose blades were thought to have an unnatural blood lust, crying out for blood at night and refusing to be sheathed until they drew blood, even resorting to cutting their owner.
 * Muramasa was the first weapon in the game to be the most powerful. That lasted until its damage and knockback were reduced and the ability to equip more than one pair of Feral Claws was removed, long before the 1.1 update when hardmode was introduced. Prior to these updates, its high attack speed combined with the knockback it caused made it nearly impossible for enemies in front of the player to come close.
 * Muramasa bears striking resemblance to the Cobalt Sword

History
Muramasa 무라마사