The following contains massive spoilers for Stranger Things Season 4, Volume 1, streaming now on Netflix.

Ever since the series premiered, one of the biggest mysteries of Stranger Things has been how Eleven's amazing telekinetic powers were truly activated and controlled. Since the first season, it's been explained that El's powers would manifest whenever she was faced with a massive emotional conflict such as fear, sadness or anger. But once her powers were awakened, they often led to devastating results for whoever was caught in her sights. Now, in Stranger Things Season 4, Volume 1, it's finally been revealed what the root cause of her powers has been all along and how it's evolved since she was a small child.

During the latest season of Stranger Things, Eleven was forced to undergo a procedure overseen by Dr. Brenner to restore her powers. His method involved El going into a sensory deprivation chamber where she would revisit memories and repave the journey she took to obtain her abilities. But in doing so, more revelations were made present such as the identity of Brenner's first subject, One. At first, One acted as an orderly who would help El handle the bigger kids who often criticized and bullied her. One told El that often what would help, at least for him, was a memory that made him both sad and angry. Initially, Eleven tapped into her earliest memory of her mother trying to take her back from the Hawkins lab before she was forcibly escorted away from El.

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Stranger Things Season 4 Peter Ballard and Eleven

Throughout the series, it was believed that El's source of strength came from her strong emotions. This was further detailed as she practiced her powers with Kali in Stranger Things Season 2. However, it may have been a further evolution from the real source of her strength: trauma. For Eleven, she's no stranger to trauma as she lived most of her early youth as a guinea pig in a research lab. But her traumas grew as she gained strength. For example, once she began to come into her powers, she quickly became one of the strongest. Unfortunately, those that she had surpassed didn't appreciate her growth and bullied her by telekinetically beating her up and threatening her life.

When One helped Eleven escape, she also freed him of an inhibitor chip that kept him from using his own powers. After he was finally freed, he took his revenge on the lab and killed nearly everyone, including the children. When Eleven realized how bad he was, she pulled the trauma from being bullied and abused, and the anger of being betrayed and losing the closest thing she had to friends. As a result, she proved even more powerful than One and opened a gateway to the Upside Down through him. While the battle was brief, it showed just how strong Eleven was and how trauma was the core catalyst.

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Eleven might be a clone of Peter/Henry in Stranger Things

After her escape, Eleven was lucky to have less trauma permeate her life. However, being a kid growing up and also facing the duties she had due to her powers, she still struggled with certain triggers. Eventually, the trauma that ignited her powers was instead relegated to moments of intense emotions. Anger was a big catalyst as she often used it to protect her friends. This was best shown in Season 1 when she protected Mike and Dustin from the bullies at the quarry.

While her early years as a telekinetic were based solely on trauma, Eleven has learned to cruise above her pain and focus on strong emotions. That said, there's no doubt that the core of her strength was born from the pain she experienced both from her peers and the betrayal of One. But in her trauma, and the apparent loss of her mother when she was young, Eleven found her strength and proved to be perhaps the strongest telekinetic in the entire series. But as she heals her wounds and overcomes the things that held her back, her strength could grow even more in Volume 2.

To see Eleven's immense power, Stranger Things Season 4, Volume 1 is streaming now on Netflix.