Justin was a Glader whose name was seen engraved on the wall of the Glade in the Maze Runner film. His name was crossed out at the time and therefore he was dead when Thomas arrived. It is unknown what he looked like or if he is mentioned.
In the Scorch Trials film, the name Justin is called for testing. However, Janson couldn't have been referring to this character, because he is dead. Nothing else is known about him.
In The Scorch Trials Official Graphic Novel Prelude, Justin is said to have been Minho's running partner and to have fallen to his death while running. He did not appear in the books and was made for the movie and graphic novel.
