The Mandalorian Protectors were first formed in 21 BBY, during the Clone Wars, by a clone known as Spar. Unlike his "brothers", Spar inherited more than his genetic makeup from Jango Fett. Spar inherited some of Fett's memories. Eight years after he was decanted to fight as an advanced clone commando for the Grand Army of the Republic, he began having dreams and flashbacks of a life that wasn't his. These memories of Jango Fett's life drove him to become obsessed with learning more about the Mandalorian culture.
He deserted Kamino and the Grand Army of the Republic and went on a search for more information on the Mandalorians. That search led him to the planet Mandalore, where he found his answers in the surviving remnants of the Mandalorians. It was there that Spar claimed the title of Mand'alor and set about rebuilding the decimated and scattered Mandalorian people. Spar founded the Mandalorian Protectors, an organization made up from local Mandalorian police forces and surviving members of both Jaster Mereel’s Super commandos and Vizsla’s Deathwatch.
Consisting of a mere two hundred and twelve members, the Protectors became the main military of the Mandalore sector and protected its borders and the people in it. Soon enough the fighting of the Clone Wars reached the Mandalore sector and Mandalore the Resurrector sided with the Confederacy of Independent Systems (CIS). The Protectors agreed to carry out covert missions for the Separatists, working as their secret police force. It was the Protectors who launched intense attacks on Kamino and New Bornalex, destroying the cloning facilities there. However, in the wake of the Republic blitz that ended the Clone Wars, the Mandalorian Protectors were decimated. Spar Survived the clone wars but was a broken shell of the man he once was, insane and crippled. He left Manda’yaim and was never to be seen again until he was found and killed in 20 ABY by Ailyn Vel, who had mistaken him for her father, Boba Fett.
But this was not the end of the Mandalorian Protectors. In 17 BBY Fenn Shysa and Tobbi Dala, who survived the the Clone Wars with Spar, returned home to Mandalore and began rebuilding. Mandalore was occupied by slavers sanctioned by the new Galactic Empire, who were exploiting their planet's most valuable resource, a metal known to the Mandalorians as beskar. Shysa recruited from among his people to form a resistance and the Mandalorian Protectors took on the role of freedom fighters for the Mandalorians.
They prevailed, killing the Suprema and driving the Imperial support forces from Mandalore in 3 ABY, toward the end of the Galactic Civil War. Their victory came at the cost of many lives, including Tobbi Dala's, but under Shysa's leadership, the Mandalorian Protectors again resumed their role as the defense force for the Mandalore sector and protectors of the Mandalorians.