Pre-Disney, the Mandalorians were a warrior people living on the planet Mandalor and several other locations. They were the instigators of the Mandalorian War.
Mandalorian was a demonym that referred to the people of the planet Mandalore. Mandalorians also lived on the moon of Mandalore, Concordia, Kalevala, Krownest and the planet Concord Dawn.
But in the Clone Wars, Duchess Satine made a point on more than one occasion to point out that the warrior past of Mandalore has been replaced by a more pacifist position
Prime Minister Almec in The Mandalore Plot (S2E12)
Master Kenobi, Mandalore's violent past is behind us. All of our warriors were exiled to our moon, Concordia. They died out years ago.
Duchess Satine in The Mandalore Plot (S2E12)
No Mandalorian would engage in such violence.
We are lead to believe that only a small group known as "Death Watch" wishes to return to the warrior past, which you get in a discussion between Duchess Satine, Obi-Wan, and Minister Almec in The Mandalore Plot (S2E12)
Not everyone on Mandalore believes that our commitment to peace is a sign of progress. There is a group that calls itself Death Watch. I imagine these are the renegades you're looking for. They idolize violence and the warrior ways of the past.
But jumping ahead a few years to Star Wars Rebels, the pacifist position of the Mandalorians is virtually ignored
- Mandalorians fought in the Clone Wars (Fenn Rau was specifically mentioned as fighting and also training pilots)
- Through out Season 3, the Mandalorian warrior heritage is very prevalent, and the Rebels specifically target them to join their cause since.
- Several episodes paint the Mandalorians as strong warriors, which seems odd given they were pacifists not 15 years before
- Imperial Super Commandos (S3E07)
- Legacy of Mandalore (S3E16)
- Zero Hour (S3E21 & E22)
So is there an explanation for the change in the Mandalorians so they are seen as warriors again? It seems odd that a society that supported a pacifist leader, remained neutral in a galactic war, and apparently had cast off it's warrior past to become sought after as warriors 15 years later. And yet, despite being pacifists and neutral in the war, had soldiers actively participating in the war.
Is the concept of the pacifists Mandalorian something that only Satine believed? Or is this an attempt to retcon a "mistake" in the Clone Wars? Or is there another explanation.