Tara Markov(imposter Terra, from Team Titans)

The second Terra was a teenager from the 21st century who traveled back to the late 20th century as part of the Team Titans. She later discovered that she was actually from the 20th century, and that the Time Trapper had placed her in the future as a sleeper agent. After her death, it was learned that she was actually from the subterranean city of Strata, and had been transformed by her people into a genetic doppelgänger of the original Terra.