Image Credit: Lucasfilm
Maul needed an army if he wanted to compete with the Republic and Separatists for control of the galaxy. By chance, Maul and Opress were found by Pre Vizla and the Mandalorian Terrorist group, Death Watch. Seeing one another as potential allies, Maul and Vizla made a deal that would give Maul his army and Vizla his homeworld, Mandalore.
Maul and Vizla soon built up their alliance by forcefully conscripting various criminal factions. Once powerful enough, Maul and Vizla led a successful attack on Mandalore. However, fearing the public’s reaction to criminal elements working with Death Watch, Vizla betrayed Maul and had him arrested. Maul expected the betrayal and used it to his advantage by challenging Vizla to single combat. The Mandalorian could not refuse and soon fell. Most of the Death Watch immediately pledged loyalty to Maul, but Vizla’s former second-in-command, Bo-Katan Kryze refused and fled.