Volcano

The Fiery Greatsword is a Hellstone weapon that has a very far reach, second only to the Blade of Grass, and very slow swing speed. It emits light in the form of fire particles when swung, which can make it useful when scouting caves and scanning for ore through walls.

It deals 34 damage, but its very slow swing speed can make it ineffective compared to the other high-tier swords, such as Blade of Grass and Muramasa.

Trivia

 * The art and name of this item may be a reference to Fiery Dragon Sword, a sword found in Guild Wars.
 * Although it's a slow weapon, Feral Claws and Shadow Armor or Cobalt Armor solve this issue, but at the cost of losing other accessory slots.