Dr. Brenner's is presumed dead after the season one finale when the Demogorgon is drawn to Hawkins Lab and attacks Dr. Brenner almost immediately. Fans believe it's the end of the man who could arguably be called a mad scientist. Though, considering the importance of Brenner's role at Hawkins Lab, it did seem a little too anticlimactic of a death. Dr. Brenner is the sole reason for the project that created Eleven and other gifted children like her. All the children called him 'Papa,' and while he does seem to genuinely care for these children, it doesn't stop him from experimenting on them.
Well, it turns out his death was a fakeout after all. While we've seen Dr. Brenner in flashbacks before, he finally makes a full-fledged return in "Stranger Things" season four. Returning to aid Eleven in regaining her lost abilities, Dr. Brenner plays a key role in assisting Eleven to revisit memories of the past that she'd rather forget: the massacre at Hawkins Lab that killed the rest of the gifted children, the incident that only Eleven survived. She's understandably suppressed the trauma of the massacre, but in order to unlock her power again, she must confront the reality of what happened that day.
