The Stalwart Shields is a company of fighting men formed in Meereen.
A Dance with Dragons
The company's members are all former slaves, known as freedmen, who are loyal to Daenerys Targaryen. Their first commander is Mollono Yos Dob, but he eventually dies from the pale mare, and Tal Toraq is now the new commander. The company appears to have been named after Stalwart Shield, an Unsullied soldier who was the first of Daenerys's fighting men to be murdered by the Sons of the Harpy.