The Wailing Wars was an undisclosed war that happened sometime before the events of Pitch Black.
During his escape from one of the Slams before he went to Slam City, Riddick joined a mercenary team who joined forces with a company of E-TAC soldiers fighting in the Wailing Wars. Riddick was the only one out of the 500 mercs who managed to leave the planet alive, which led to speculation that Riddick killed most of his own platoon. 
The ship that would be later known as the Dark Athena was created prior to the Wailing Wars.
William J. Johns also became a merc during the Wailing Wars.
- The event is called "Wailing Wars" in Pitch Black Blackbox and in Hunt for Riddick, but "Walling Wars in Ursa Luna Prisoner File and Assault on Dark Athena Bonus Content.