The Death Watch was a Mandalorian splinter group that opposed the pacifist government of Mandalore led by Duchess Satine Kryze during the Clone Wars era.
After failed attempts at taking over Mandalore, they became part of Darth Maul’s Shadow Collective which successfully took control of the planet during the war.
Following the end of the Mandalorian Civil War, the Mandalorian Warriors were exiled to the moon of Concordia where most of them died out.
However, the survivors regrouped and began calling themselves the Death Watch.
They were then led in secret by Concordia’s governor, Pre Vizsla of Clan Vizsla and Duchess Satine Kryze’s sister, Bo-Katan.