Dr. Brenner from season one was a research scientist ... Teasing a character death at the end of the season isn't new to "Stranger Things." In season one, it was suggested Eleven had died, only ...

One of them is Martin Brenner (Matthew Modine), the ominous doctor ... "Stranger Things" comeback, though. Dacre Montgomery's Billy Hargrove is a formidable presence throughout seasons 2 and 3 ...