David Harbour says is his favorite one yet because of the things his character gets to do. Presumably, that means breaking out of the Russian prison camp he was last seen in. Only time will tell how he manages to do that.
While Hopper has been a formidable presence on the show, protecting Eleven and her friends from everything the Upside Down throws at them, not much is known about his past. We do know Hopper's daughter Sara died before the events of the series, leading to the divorce of him and his wife Diane. Hopper's struggles with alcoholism and prescription medication was a result of Sara's death, but that plot was largely pushed to the side once things in Hawkins started to kick off. However, more about the character's past will be revealed in the season.
In an interview with People, Harbour revealed that Hopper may have to start dealing with some of the traumas from his past that he has pushed aside. Harbour says that fans will get to see a warrior side to Hopper in his backstory. However, he also says that many of Hopper's past mistakes will be brought to light, coming back to haunt the Hawkins chief of police. Harbour said, "You really do get to see a lot of his backstory of who he was as a warrior in a sense and sort of the mistakes he made in the past come back to visit him."
It seems like Stranger Things season 4 will be somewhat of a reckoning for Hopper. Not only will he have to contend with escaping from the Russian prison camp, but he may have to deal with his demons as well. The consistently wild events in Hawkins have largely prevented him from doing that. Hopper became very protective of Eleven after the events of the first season, dedicating his time to protecting her as his surrogate daughter. Now that he's all alone in Russia, those demons he has kept at bay for so long may finally be coming to the surface.
Another interesting aspect of Harbour's quote is the warrior aspect of it. While the Hawkins chief of police has also shown a willingness to fight for who and what he loves, Stranger Things season 4 will take that to a whole new level. With Hopper stuck in the Russian prison camp, he will have to deal with a whole new type of enemy, one that may be even more ruthless than the demons in the Upside Down. Details have been pretty scarce about Stranger Things season 4 so far, but with production back up and running, Harbour has been pretty open about revealing his excitement for the season. There's no word yet on when the show will hit Netflix, but it is expected sometime in 2021.
Source: People