Nine is one of the known test subjects at Hawkins Lab as of 1979. She was one of those killed by One on September 8, 1979. She is portrayed by Chloe Adona.
Adona says her "ideal superpower" for Nine would be telepathy and mind control.
There are roughly one-sh*t billion tropes so PLEASE look through them before adding one. Otherwise add what you like. ADDITION: PLEASE read through the trope description provided before submitting something. It's not a huge deal but too often people submit characters that don't fit just because they misinterpreted the title...
