Thomas Jr. is the son of Catman and Cheshire. Thomas Blake, Jr. is named after his father, Thomas Blake or Catman. His father first met him when the Secret Six went to Cheshire's hideout in the Himalayas, where Cheshire revealed the boy to his father.
He was kidnapped, as a way to get at his mother. His kidnappers had him adopted. The man funding the kidnapping told Catman that it was better this way, that no one would kidnap him again, and he would be safe. Catman kills his son's kidnappers, but leaves his son where he is.