«Gun Gale Online» (ガンゲイル・オンライン, Gangeiru Onrain?, abbreviated as GGO) is a VRMMORPG, developed and operated by an American company called Zaskar, that emphasizes on gun usage. It is the setting for the Phantom Bullet Arc. One of the main events in GGO is the multi-player versus player tournament known as the Bullet of Bullets (BoB). The game started operation in April 2025 and has become the most famous Sci-fi VRMMO game in the Sword Art Online Universe since then.