SPOILER WARNING: This article contains major spoilers for "First Light," the series premiere of Cloak & Dagger.
The source of Cloak & Dagger's powers may not be as mysterious as it seems to be. Since their superhuman abilities tie back to Roxxon Oil Corporation, which has quite a lengthy history in the Marvel Cinematic Universe, we can trace this source to its very beginning -- and it seems like Cloak & Dagger has everything to do with a little thing called Darkforce, which was introduced in Agent Carter Season 2.
After the development of the atomic bomb in the 1940s, several of the MCU's big name tech companies -- including Stark Industries and Roxxon -- engaged in an atomic arms race. One of these companies, Isodyne Energy, accidentally stumbled across the Darkforce in the process. Originally called Zero Matter, Darkforce was an element comprised entirely of pure negative energy with some mystical attributes.
During an atomic experiment conducted by Isodyne, an anomaly shaped like a giant crack in reality formed at the test site. A nearby military team was subsequently sucked into it, never to be seen again. The crack then disappeared, leaving only a puddle of Darkforce matter behind in its wake.
"There's no fit for it anywhere on the period table. Zero Matter is unlike any substance that we have ever seen," Isodyne scientist Jason Wilkes explained to Peggy in the second episode of Agent Carter Season 2. "I have a hypothesis. Do you know what a perfect fluid is? Real fluids conduct heat and have viscosity. Perfect fluids have no sheer stresses, no heat conduction. You see, Zero Matter is always drawing energy into itself. It'll always be the coldest object in the room because it is literally devouring any nearby energy."
Indeed, another Isodyne employee found this out the hard way. When scientist Jane Scott touched the Darkforce, she was frozen solid, kicking off the murder investigation that led Peggy right to Isodyne.
According to Wilkes, he had to "build and maintain the magnetic containment chamber" -- the only way Isodyne could handle the substance. He believed it "could be extraterrestrial. Could be extradimensional," the latter of which tracks with its nature in the comics. "The place where Zero Matter comes from, it's dark, painful. It's not a place you want to be," he added in the episode "The Atomic Job."
Later in the episode, Wilkes and season antagonist Whitney Frost had a close encounter with the Darkforce. As Wilkes attempted to steal the Darkforce from Isodyne, Frost tried to stop him. They dropped the container holding the element in the process, breaking it open. Freed from its confinement, the Darkforce released a pulse of energy so strong that Peggy felt its effects outside the building. Intriguingly, this energy pulse visually mimicked the one from the Cloak & Dagger series premiere, when the Roxxon rig fell into the lake and exploded.
By the time of Cloak & Dagger, Isodyne Energy was long gone -- but its assets weren't. Per the Agents of S.H.I.E.L.D. Season 4 episode “The Good Samaritan,” Roxxon acquired Isodyne Energy on October 13, 1956. As Leo Fitz explained to Alphonso “Mack” Mackenzie, “Peggy Carter and her team encountered them back in the 40s. They were conducting experiments on something called Zero Matter, or Darkforce, but Isodyne doesn’t exist anymore. Its assets were acquired by Roxxon Corporation in the 50s.” This indicates that Roxxon is in possession of whatever Darkforce Isodyne had left over, which suggests Darkforce may have been involved with the Roxxon rig explosion in Cloak & Dagger.
“There’s obviously a couple of moments in Agent Carter that we made sure we watched, to make sure that everyone understood that it is all connected," showrunner Joe Pokaski teased at WonderCon back in March.