The Harun-El, also known as the Rock of Yuda Kal; referred to as Black Kryptonite by Lena Luthor, is a mineral with a mutagenic effect and seemingly magical powers, originating from the planet Krypton. It can be used as a source of energy.
Harun-El was used on Krypton by the Children of Juru to make the Worldkillers. On their homeworld or in Argo City, it is harmless to Kryptonians but on Earth, the substance becomes toxic to Kryptonians and can be used to split a Kryptonian in two, such as when Lena used it to split Reign (evil) and Samantha Arias (good). When Kara used it to send herself, Reign, and Sam into the Dark Valley to defeat Reign without casualties, it split Kara in two, sending the other half to Kaznia unbeknownst to her.
Harun-El is also an incredible power source able to power the dome of Argo City as well as sustain an ecosystem and the artificial gravity on the asteroid that houses Argo. Argonians now have a recipe to make the substance from elements on Argo, courtesy of Lena who figured out how to make it.
The Harun-El can be used to synthesize a chemical compound that would bestow a human being with extraordinary abilities.
- Strength augmentation: The Harun-El seems to enhance the user's strength to the point where a human can physically combat solar-powered Kryptonians.
- Regenerative healing: The Harun-El even bestows its user with a regenerative healing factor. Upon injecting himself with the Harun-El, Lex Luthor healed himself from his self-inflicted cancer and upon Lena injecting James Olsen, he regenerated from his lethal wounds. When Lex used his Harun-El empowered blood to give Red Daughter a blood transfusion, it managed to regenerate her form her illness and stabilize her physiology.
- Sensory augmentation: Due to being injected with the Harun-El, James Olsen can "zoom in" on people or things at a distance and can even hear more than a normal human.
Behind the scenes
- The concept of Kryptonite that grants humans superhuman powers was previously featured in Smallville, where various Kryptonite-afflicted meta-humans were the near-exclusive antagonists of the early seasons. However, in Smallville, the mutations were caused by Green Kryptonite.