Nod is a character, nobody knows what he/she does look like, just like Squeek, nobody knows
how he is. Oddworld: Nod's Oddysee was a game where Nod is the main character,
sadly this game never became avaliable. :(

Q&A VI
Use your browser’s search feature (likely Ctrl+F) to look for ‘Nod’. There should be four questions listed there that address the Nod character. Click the links, and read the answers.