Dr. Martin Brenner's (played by Matthew Modine) first appearance was in season one, episode one.
he is the head hancho of experimenting on children. He listens to conversations
on phone calls in the lab, and chases Eleven down.
Other relations
Eleven (test subject) Henry Creel(test subject)
Jim Hopper(enemy) Jack Sullivan(enemy) Terry Ives(former test subject) Dr. Sam Owens(colleague)
Dr. Martin Brenner(enemy) Joyce Byers(enemy)
In season one, Brenner hunts for Eleven to bring her
back to the lab so he can use her powers to help look forHenry and bring him back.
He looks for her with clues from phone calls people have in Hawkins and disappears
when he gets attacked by The Demogorgon at the middle school the party were hiding at.
In season two, he appears as a vision Eleven is having due
to her sister Kali.
In season four, Brenner appears again and gets Dr. Owens
to take Eleven to NINA so he can help her get her powers back.
He tries to convince her that she was only going in the Void to study the soviets.