Merva's shawl was a rendering from a floating castle at the Brink. It "makes a semblance obey whoever puts it on them" (1:131). Cole obtained the shawl on his first mission. A woman semblance put it over him to obscure him from the other semblances. He retained the shawl after fleeing the castle. It did not obscure Cole from semblances on other castles.
Later, the shawl was used to help Lyrus become self-aware. Using the Shawl, Cole and Lyrus made a deal, but Lyrus made the deal in such a way as to obtain his true purpose, which inadvertently resulted in destroy many Sky Raiders and killing Durny.
The shawl was used to command the Carnag-Miracle semblance to return Miracle's power to her. The shawl was destroyed by fire during the power transfer.