Dr. Martin Brenner is the secondary antagonist in the Netflix original series Stranger Things. He is portrayed Matthew Modline.
Most of Brenner's past remains a mystery, expect that he was involved in a controversial project under the codename MKUltra. Despite the failure of the project, he managed to kidnap Jane Ives, the child of Terry Ives, a volunteer of the program and he raised her under the name of "Eleven." Eleven had developed powers because Brenner had experimented on her mother while she was pregnant with her. Brenner taught her to use the powers she developed to spy on Russians. Brenner had her make contact with the Monster, which somehow opened a gate to the Upside Down in Hawkins Lab.
After Eleven managed to escape one night, Brenner and the rest of the government began searching for her and the Monster. They soon found out that The Monster managed to kidnap a boy named Will Byers; Brenner then worked to cover this up with a fake death. He then found that Eleven was staying with a group of boys. He managed to locate her in Hawkins Middle School and attempted to take her back to the lab. Eleven killed both Agent Frazier and most of his co-workers using her power of biokinesis, and the blood from this attracted the Monster, allowing Eleven to escape Brenner once again, Brenner is then attacked by The Monster . It is unknown whether if he was either killed or got badly injured afterwards.