Ghost Online is a 2-D sidescrolling fantasy MMORPG from Korean company MGame. The game is also known as Ghost Soul, from its system that lets players absorb the souls of monsters they defeat. Ghost has the typical quests and hunting for character advancement, and the limited customization of most free-to-play MMOs.

The story concerns a demon hunter who used forbidden powers and was corrupted in the process. A attempt to cleanse his own soul ends up with him being reincarnated as the player character. All characters begin as peasants and can work their way up into one of five class paths -- Warrior, Assassin, Goliath, Treasure Hunter, or Magician/Taoist. Monsters in the game come in several types based upon both method of attack and manner of movement (such as flying), but all the bosses are hybrid animal/humans with design inspired by the twelve animals of the Chinese zodiac.

Ghost Online was free to play and item shop supported. Its US publisher MGame canceled it in 2009, and the global version soon followed.