The 42-year-old actor spoke about the upcoming installment of the science fiction-horror web series, reported The Independent.
Harbour described the first episode of forthcoming season as "fun and dark and complex" and added how his character has developed since the first season, while doing an Ask Me Anything on Mogul. In this bout, Hopper's character will now battle both his inner and outer demons.
He said, "He saved will and has found a renewed interest in life. So his arc for season two in my mind becomes more about butting up against the places where his hero fantasy can't take him.
"Stranger Things" season two airs on Netflix at Halloween later this year.