who knows what Anti-Jacob should be called. You can call Anti-Jacob any name you want. They never said Anti-Jacob's name so whose to say you're wrong?
Whatever his name is, he appears to be opposite of Mr. Jacob, or as I like to call him, MiW. Or Mr. J you prefer. This guy seems to wear opposite colors and seems to be an enemy of Man #1. Almost like he is the Antithesis of Fish Boy.