Tor Vizlsa was the kinsman of the current Death Watch leader Pre Vizsla. He battled several Jedi too with the Dark saber.
He battled Jango Fettseveral times and he was eventuallly killed. By wild cats after he lost consciousness following a battle with Jango. However, befoe he died, he had created the Death Watch.
Death Watch was created to try to bring back the old warrior days of Mandalore. Tor and his groupies didn't like how the Government had changed and Mandalore became peaceful. After Tor's death, when the New government was formed, they had banished the warriors to the Mandalorian moon, Concordia to Die off. However they didn't. When Pre Vizlsa became the leader of the secret organization the Death Watch came into prominence.