At some point in the past, his face was burned by Shaw, leaving him with a scar. When Chuck and Sarah successfully swapped out the Mask, Vassilis mistook Chuck for the agent in charge, believing he used Sarah and Hannah to gain access to the vault. He attempted to use Hannah to force Chuck to return the mask, but was duped with a duplicate, which Chuck smashed to make him believe the weapon was released. As he fled the scene, he saw Shaw with Sarah, and reported to the Ring Elders that Shaw was still alive. Vassilis was quickly executed for his failure. Seen in: "Chuck Versus the Mask".
The name would appear to be Greek, presumably giving him some link to the Macedonian Alexander.