This is from the Guild Wars 2 Fanday. Here Rytlock gives the player some more information before entering the Catacombs dungeon.
The Foefire is the event in 1090 AE that decimated the human and charr forces during the final siege of Ascalon City, which finally ended the conflict surrounding the city. When an overwhelming charr force invaded Ascalon, led by the imperator of the Flame Legion, the human soldiers failed to stop the charr advance.
Enraged, King Adelbern refused to admit defeat and, standing at the top of his highest tower, unleashed the power of his magical sword, Magdaer.
A sword made of white fire consumed the tower and soon spread to the entire city, killing all charr within the city and transforming all human leagues around Ascalon City into enraged ghosts.