Sinister Separations of Split Super-Sisters

Red Kryptonite in the Earth-One universe originated when Green Kryptonite passed through a scarlet colored cosmic cloud, altering its chemical composition. It had random effects which temporarily transform Kryptonians exposed to it into a variety of states for 48 hours. Such was the case when Kara Zor-El aka Supergirl, upon contracting Red Kryptonite radiation, split into two distinct women with separate identities.

Although there was Red Kryptonite in the Earth-Two universe, it didn’t have the same effect on that reality’s Superman and his cousin Power Girl. However, another remnant of her Krypton had the effect of splitting her in two. While her counterpart split into two physical bodies, the effects of the Symbioship which carried her from her home world to Earth-Two instead extended her lifespan by decades! Still, she two ended up with two different psyches, one inside her spacecraft and one outside it. This would cause long-lasting effects, evident years later when she joinedhumanity.

The clone created by Red Kryptonite disguised herself under the masked identity of Satan Girl, and used a device to siphon the ruby radiation from her body and transfer it onto the bodies of the female members in the 30th century Legion of Super-Heroes. Despite their superior numbers, the male Legionnaires along with Supergirl were unable to retain her twin Satan Girl and revitalized their female colleagues. Only the timely intervention of the Legion of Super-Pets helped save the day for the Legionnaires, while Supergirl's corrupt clone merged back into her body.

A second Power Girl was spawned during the Crisis on Infinite Earths, when the Kara Zor-L of the reality where all Earths including hers merged into one composite Earth. Eventually, she found her way back to her native Earth-Two, in a timeline which like on other Earths such as Earth-One and Earth-S it remained in a separate reality. When she arrived in her home universe, she reaquainted herself with her colleagues in the Justice Society of America as well as her best friend, Helena "Huntress" Wayne. Together, their World's Finest Females together confronted the Joker and brought him to justice for his heinous actions against humanity and against Helena's boyfriend Harry Sims. Soon after this, the Kara Zor-L of this Earth-Two's timeline returned after a length journey in space.

Despite appearances to the contrary, Satan Girl was alive and well as Nightflame, back in the 20th century where she was shunted to the pocket dimension of the Innerverse. As it started to collapse, Nightflame sought to steal the life of the woman she was cloned from, and nearly defeated Supergirl. Yet during their battle, the heroine gained the upper hand and seemingly doomed her evil doppelgänger.

Upon seeing their twin, the Power Girls battled one another, with the one who survived the Crisis and the end of her universe initially defeated by the Power Girl of this reality. This led one Kara Zor-L into a murderous rage, while the other felt alone and abandoned. With the intervention of the Justice Society, the two Girls of Steel eventually ended their fisticuffs and parted peacefully. Both Kara Zor-Ls resumed their heroic legacies in parallel planes of existence. 

Evidence suggests that the supervillainess formerly in the 30th century as Satan Girl and "later" (from Supergirl's perspective) in the 20th century as Nightflame remained alive, although changed from her last experience battling the original Kara Zor-El. Only a few scant months from when Nightflame disappeared, the mysterious masked maiden known as Black Orchid appeared. Evidence suggests that these two women were one in the same, although now this former Red Kryptonite clone abandoned her evil ways and sought to expose injustice from within.

Garbed in a purple spandex body suite including a hood and cape reminiscent of Satan Girl, Black Orchid masqueraded as various women who infilitrated into criminal networks. In her assumed identities, she gained their trust until the time was right to transform into Black Orchid, and add to her knowledge of these crooks' misdeed her substantial physical abilities. These included superstrength, flight, and other Kryptonian level powers. In fact, in one case involving Superman and the Super Friends, Black Orchid seemed to be momentarily affected by Green Kryptonite. However, her Red Kryptonite metabolism protected her, as she brought her arch-enemy to justice.

Karen Starr II was spawned from the energies emitted by her Justice Society teammates Green Lantern, Doctor Fate and Starman. This occurred when that four along with the Huntress found themselves exiled in a temporally altered Earth-Prime, contaminated by the insidious influence of time tyrant Per Degaton. Tracking the villain back to 1942, these five JSAers entered their home reality of Earth-Two and teamed up with the All-Star Squadron a five members of Earth-One’s Justice League of America. Together, the three teams tackled Degaton, his army and the Crime Syndicate of Earth-Three.

It is unknown how long in the original timeline this future Power Girl along with her Justice Society allies resided in the 1940s. While her past self was still slumbering in a virtual reality aboard her red Kryptonian craft traveling through space towards Earth-Two, this Power Girl possibly had her own life and career during the golden age of superheroes when her cousin Kal-L aka Superman was himself a young man. However, when reality returned to normal, this Power Girl and her allies disappeared from that era.