Terraria (Wiki): Enchanted Sword

The Enchanted Sword is a melee weapon that pierces enemies without consuming ammunition or mana.

The Enchanted Sword fires an Enchanted Beam projectile when swung. It has the same damage as a sword, is unaffected by gravity, and dissipates when it collides with a solid object like a wall or an enemy. 

The Enchanted Sword can be considered a counterpart to the Enchanted Boomerang, and it is one of the key components in crafting the Zenith. An Enchanted Sword can autoswing. Its attack reaches two tiles in radius. At an optimal distance, the Enchanted Sword can pierce two enemies. However, multiple bodies will be damaged should they all line up for the player.

When normally used, the Enchanted Sword and its projectile produce lingering sparks that emit large amounts of light, making it suitable for exploring caves, finding ores, and lighting dark places when traveling. Its attacks do not go through walls. 

Fired projectiles have a cooldown of 0.75s. During this time, the player cannot use Auto Select, switch between items, or look in another direction. However, they can still swing the sword. The player will be alerted that an Enchanted Beam has been recharged by a small particle effect and the mana regeneration sound (3DS, old-gen consoles). The Enchanted Beam's speed will vary depending on melee speed. However, the cooldown will not change.

Combat-wise, the Enchanted Sword is a powerful early-game weapon that, if discovered early, can rival many pre-Hardmode melee weapons thanks to its respectable damage and projectile. All Flask items will imbue their unique effects since the Enchanted Sword is a melee weapon.

The Enchanted Sword is best modified with Legendary for overall stats improvement.