The Mandalorian Theory: Moff Gideon Built the Dark Troopers With Beskar 

screenrant.com -BY RICK STEVENSON - Moff Gideon's Dark Troopers are particular fearsome in The Mandalorian, and that could be because they're made using stolen beskar steel.
Keywords: the mandalorian, theory, moff gideon, built, dark troopers, beskar