Imperiex is a fictional character that appears in comic books published by DC Comics. The character first appears in Superman (vol. 2) #153 (February 2000), and was created by Jeph Loeb and Ian Churchill. He was the main villain for the "Our Worlds at War" crossover.

The embodiment of entropy, Imperiex takes the form of pure energy contained inside a humanoid set of armor, colossal in size. He is first mentioned when Mongul, the son of the deceased villain of the same name, arrives on Earth stating that Imperiex has destroyed his Warworld and is heading for Earth. Mongul convinces Superman to help him fight Imperiex, and the two apparently manage to defeat it. However, it transpires that the "Imperiex" they encountered was no more than a probe, whereas Imperiex Prime, leader of the Imperiex probes, is himself a much larger and more powerful being. He has detected imperfections in the fabric of the universe, and his ultimate plan is to destroy it and create a new, perfect one. To do so, Imperiex Prime heads for Earth- the planet which holds the universe together after being the center of the Crisis on Infinite Earths, in order to destroy it and thereby induce a new Big Bang.

Power Girl (real name Kara Zor-L, also known as Karen Starr) is a DC Comics superheroine, making her first appearance in All Star Comics #58 (January/February 1976).

Power Girl is the Earth-Two counterpart of Supergirl and the first cousin of Kal-L, Superman of the pre-Crisis Earth-Two. The infant Power Girl's parents enabled her to escape the destruction of Krypton. Although she left the planet at the same time that Superman did, her ship took much longer to reach Earth-Two.

Possessing superhuman strength and the ability to fly, she is a member of the Justice Society of America and the team's first chairwoman. Power Girl sports a bob of blond hair; wears a distinctive white, red, and blue costume; and has an aggressive fighting style. Throughout her early appearances in All Star Comics, Power Girl was frequently at odds with Wildcat, who had a penchant for talking to her as if she were an ordinary human female rather than a superpowered Kryptonian, which she found annoying.

The 1985 limited series Crisis on Infinite Earths eliminated Earth-Two, causing her origin to change; she became the granddaughter of the Atlantean sorcerer Arion. However, story events culminating in the 2005-2006 Infinite Crisis limited series restored her status as a refugee from the Krypton of the destroyed pre-Crisis Earth-Two universe. She was ranked ninth in Comics Buyer's Guide's "100 Sexiest Women in Comics" list.