Born Jane Ives on June 7, 1971, Eleven is the daughter of Teresa "Terry" Ives. Terry was one of the test subjects in MKUltra, a real-life Central Intelligence Agency (CIA)-sanctioned program where the government conducted mind control experiments on real people. According to the series, Terry joined the program as a college student in 1969 under the supervision of Dr. Martin Brenner. Terry was subjected to experiments, including drug testing, psychedelic drugs, and being submerged in sensory deprivation tanks. 

11 is the fan favrite I feel bad for her because she was used for exparments as a kis but she dose have cool powers and is the main threat to vecna the main villan.