Question

In the first book Divergent, How did Tris find out what Fours' real name is and what is it? Who gave Four the nickname Four?

Answer 1

In the first book Divergent, Beatrice or Tris Prior, found out Fours' real name when he let her into his fear landscape. Fours' real name is Tobias Eaton.

The person that gave Four his nickname is Amar, his instructor in Dauntless