Pre Vizsla publicly served Duchess Satine as the governor of Mandalore's moon Concordia, but was really the leader of the Death Watch, a secret society of Mandalorian commandos who sought to overthrow Satine's government and reclaim the Mandalorians' honor as warriors.
Vizsla and Count Dooku plotted to assassinate Satine, which would lead to a Republic occupation of Mandalore. Vizsla's Death Watch would then liberate the planet, joining the Separatist cause.
Things did not go according to plan, and Vizsla and Dooku bitterly parted ways. Death Watch became a group of nomadic warriors, with the formerly manicured and orderly Vizsla becoming unkempt and battle-worn as their leader.