Terraria (Wiki): Ice Blade

The Ice Blade is a melee weapon that pierces enemies without consuming ammunition or mana. Its Hardmode upgrade is the Frostbrand.

The Ice Blade is a sword that fires an Ice Bolt projectile with a cooldown of 0.92s when swung. The Ice Bolt projectile is unaffected by gravity, deals equal damage to the sword, and vanishes upon impact with an opponent or a solid object.

The player can still swing the sword while the cooldown is in effect, but they are unable to switch between items, look in another direction, or use Auto Select. An Ice Blade can autoswing. Its attack reaches three tiles in radius. At an optimal distance, the Ice Blade can pierce two enemies. However, multiple bodies will be damaged should they all line up for the player.

When normally used, the Ice Blade emits light, making it suitable for exploring caves, finding ores, and lighting dark places when traveling. The player will be alerted that an Ice Bolt has been recharged by a small particle effect and the mana regeneration sound. The Ice Bolt's speed is influenced by melee speed. On the other hand, its cooldown will not change. 

When its projectile is fired, the Ice Blade makes the same noise as the Ice Elemental. The Ice Blade's melee attacks do not go through walls.

Combat-wise, the Ice Blade's autoswing, 17 damage, and projectile can make it a good melee weapon in the early stages of the game. All Flask items will imbue their unique effects since the Ice Blade is a melee weapon.

The Ice Blade is best modified with Legendary for overall stats improvement.