Alexander Luthor Jr.

Born on Earth‑Three to the Earth‑Three versions of Lex Luthor and Lois Lane, Alexander was placed in an experimental device by his parents to escape the Anti‑Monitor's antimatter wave. At the Monitor's request Harbinger retrieves him and he materializes on the abandoned satellite that had been the Justice League's headquarters. His passage through the antimatter storm accelerates his aging and later ties his nature to matter/antimatter phenomena; after the Crisis event he retreats with three other survivors into a separate dimension.

Sources describe rapid physical aging: during Crisis on Infinite Earths Alexander ages from infant to young adult within weeks, and by the events of Infinite Crisis he is described as having been rapidly aged to his mid‑30s. In Infinite Crisis he is discovered in an alley after being mutilated—his face is slashed by the Joker—and then shot in the head by the Joker, resulting in his death. Comics synopses provide episodic visual details tied to these events rather than a single standardized costume description.

Alexander's passage through the Anti‑Monitor's antimatter storm is described as granting him power over matter and antimatter and producing accelerated aging. He and three other Crisis survivors later possess power over their post‑Crisis pocket dimension, which reacts to their thoughts and emotions. He is described as possessing a genius‑level intellect and masterful manipulative skills: he masquerades as Lex Luthor, forms a new incarnation of the Secret Society of Super Villains, constructs a dimensional 'tuning fork' from Anti‑Monitor remains to attempt to recreate the multiverse, grants sentience to the Brother Eye satellite to serve his tower, and manipulates the Spectre into destroying magic in order to harvest its raw form. After his death he is briefly resurrected as a member of the Black Lantern Corps during Blackest Night.