God of War is an action-adventure video game series loosely based on Greek mythology. Debuting in , the series has become a flagship title for the PlayStation brand, consisting of seven games across multiple platforms. The series' story centers around its only playable character, Kratos, a Spartan warrior tricked into killing his wife and child by his former master, the God of War Ares. Kratos eventually kills Ares at the behest of the goddess Athena and takes his place as the new God of War, but is still haunted by the nightmares of his past. Kratos is eventually betrayed by Zeus, the King of the Olympian Gods. Revealed to be a demigod and the son of Zeus, Kratos now seeks revenge against the gods for their machinations. What follows is a series of attempts to free himself from the influence of the gods and the Titans and exact revenge. Each game chapter forms part of a saga with vengeance as a central motif.