Kagemitsu G4

«Kagemitsu G4» is a light saber owned by Kirito in Gun Gale Online. Currently, it is under Sinon's possession.

Gun Gale Online
Kirito bought «Kagemitsu G4» because it's the only weapon he found that resembles a sword, since he was used to clashing with swords in Sword Art Online and ALfheim Online.

Trivia

 * It was introduced to the game as a whim of the creators to resemble the movie Star Wars.