Excalibur

is the base weapon that Arthur uses in battle. It allows its user to mold a concentrated blade of plasma, a state of matter, created by heating up flames to extreme temperatures, on the handle of a bladeless sword, giving it a blade in the process. Such process requires the wielder to use their. As noted by Takehisa Hinawa, the swordplay using Excalibur is equivalent to plasma cutting.

Trivia

 * The weapon is named after Excalibur, a legendary sword used by King Arthur, which was attributed with magical powers.