In the story of Eleven from the series Stranger Things, much attention is paid to her relationship with Jim Hopper, who saved the girl who escaped from the villains and became her guardian. At the same time, many are interested in who is Eleven's biological father?
Some may think that it is Dr. Martin Brenner from Hawkins Laboratory, where Eleven grew up, because she called him dad. But Brenner acted as a father only in her subconscious, because he kidnapped the girl immediately after birth. But the heroine's real dad is different.
For example, in the official prequel novel based on the original series, it is said that Eleven's mother, Terry Ives, dated Andrew Rich, who died in the Vietnam War without ever knowing about Terry's pregnancy.

As it turns out, it was Dr. Brenner who set up Andrew's deployment to Vietnam. He did this to punish Terry for finding Kali in the lab, another girl who, like Eleven, was being experimented on.