In the womb, Eve was experimented as an object for the government. There are so many tests to hopefully be successful to have an unborn child with unimaginable powerful powers and a mental block attached to be unable to each full potential. You, her twin sister, didn't receive any powers in the womb, so she had to experience that pain.

When both of you were 13 and she was experienced in her powers and how it works, she made a promise that she would be by your side to protect you. No matter what. Eve kept it alive. At the age of 19, she helped you through many problems despite your parents, especially your father discouraged what she did, but she didn't care. You were the only person she cared for.