Mythril Bar

Mythril Bars are a type of Hardmode-bars made from Mythril Ore. They are necessary to make the Mythril Anvil, which in turn is needed to make most Hardmode equipment. The Mythril Drill and Mythril Pickaxe are the first tools acquired that are capable of harvesting all but two block types in the game (exceptions being Chlorophyte Ore and Lihzahrd Bricks).

On the, Mythril Bars drop from Shadow Hammers.

To craft all Mythril equipment, the player needs to acquire 153 /  155 bars, or a total of  612 /  620 ores.

Trivia

 * is a fictional metal in J.R.R. Tolkien's Middle Earth writings, where it is a rare and high-quality material used for weapons and armor. It has become a widely used material in fantasy works, particularly video games.