Cobalt Sword

The Cobalt Sword is a sword crafted using Cobalt Bars and is one of the materials to craft Excalibur. It bears a strong resemblance to the Muramasa and can be swung continuously, also much like Muramasa and Phasesaber. It can also swing faster than the Mythril Sword and the Adamantite Sword.

Trivia
The Cobalt Sword bears a resemblance to a Japanese Katana, and fits with the "Feudal Asia" theme that the other cobalt weapons/armor seem to have.