We know that Sauron will eventually forge nine rings for men, and the wearers of those rings will be corrupted and become ringwraiths or Nazgûl. The ringwraiths serve Sauron and they're the hooded ...
They are the second batch of Rings of Power, forged after the three Elven Rings in Season 1. In the books, however, they are forged first, together with the Nine Rings for Men, by Celebrimbor ...