Dr. Martin Brenner, portrayed by Matthew Modine, is a significant character in Stranger Things, particularly in relation to Eleven. Brenner, who allegedly worked for the US Department of Energy, was a government figure involved in controversial experiments. He raised Jane, who he referred to as Eleven, along with several other child test subjects. Brenner built himself up as a father figure to these children, making them refer to him as 'Papa'. Despite his seemingly caring demeanor, Brenner's actions were far from paternal, subjecting the children to various inhumane tests and experiments.