While imprisoned inside the Phantom Zone, the Kryptonian known as General Zod and his mate, Ursa, gave birth to a child named Lor-Zod. While living inside of a transported Kryptonian prison cell known as Fort Rozz, Zod manipulated Phantom Zone technology and created a small space-worthy vessel that could maintain a substantial form and leave the Phantom Zone. As his son was the only Phantom Zoner capable of maintaining a physical form, Zod sent the rocket ship out of the Phantom Zone carrying their young son. The rocket entered Earth's atmosphere and would have crash-landed in the heart of downtown Metropolis, but for the timely arrival of Superman. Recognizing that the child was of alien origin, he reluctantly left him in the care of Sarge Steel and the Department of Metahuman Affairs. Lor-Zod stunned everyone when he lifted a three-hundred pound television cabinet above his head with no effort. After hearing the child speak, Superman immediately recognized him as Kryptonian. Steel insisted on keeping him overnight for observation. Scientists ran oral DNA tests to determine whether the boy truly was a Kryptonian.
Lois Lane wrote the exclusive story on the child's arrival on Earth in the Daily Planet, and the news quickly spread across the globe. The Department of Metahuman Affairs relocated the unnamed Kryptonian to a secure location in Washington, but neglected to inform Superman of the transfer. Enraged, Superman broke Lor-Zod out of custody and brought him to the Kent farm in Smallville.
Determined to keep him safe from the government and from scientific persecution, Clark asked Lois if she would agree to adopt the boy with him. Lois remained uncertain of her capability regarding parenting, but quickly acquiesced, and even supplied him with an Earth name – Christopher.
The Department of Metahuman Affairs was not the only source of interest in regards to "Christopher Kent." Lex Luthor, secretly monitoring Sarge Steel's broadcasts, learned of the child's Kryptonian origin and set about claiming the boy for himself. Having somewhat trained the creature known as Bizarro to do his bidding, Luthor sent Bizarro into the city to capture Lor-Zod. A fight broke out between Bizarro and Superman, and Lor-Zod demonstrated his Kryptonian invulnerability by surviving the impact of a school bus falling directly on top of him.
Shortly after the battle took place, Lor-Zod's birth parents, General Zod and Ursa, broke free of their Phantom Zone prison and arrived on Earth to find him. Collecting Lor-Zod, the criminals freed the rest of their Kryptonian brethren from the Zone and mounted a massive invasion of Earth. During the siege of Metropolis, Lor-Zod turned against his father, burning his hand with twin blasts of heat vision. After the defeat of his biological parents, Lor was adopted by Kal-El and his wife, Lois, who decided to raise the boy on Earth as their foster son with the name of Christopher Kent. Chris accepted the younger Kents as his parents, and Clark's foster parents as his own grandparents, even calling Lois "Mama Lois" as he adapted to life on Earth.
When Zod and Ursa and their associates broke free of the Phantom Zone a second time, they attacked Kal-El and his family. Zod and Ursa recaptured Christopher as a bargaining tool to intidimate Superman into surrendering. However, Superman was able to hold off Zod and his criminal allies until Luthor's technical assistance was able to exploit the connection that all the Kryptonians who had been in contact with the Phantom Zone possessed and forced them to be drawn back into it. Unfortunately, this link was also inclusive of Christopher, who was born in the Zone, and even Superman, who had some interaction with the Zone. Seeing that the Zone portal would not close after all the criminals had been sucked back in, Christopher chose to sacrifice himself to close the breach rather than let it continue, possibly causing more damage to the city and swallowing his foster father.
When Superman contacted his "cousin" Mon-El, who remained in the Zone due to his own radiation poisoning to find out about Christopher's fate, Mon-El informed Kal-El that Christopher was either not in the Zone or was transferred to some very remote locale within the Zone that no one knew of.
Main article: Superman: New Krypton In truth, it was the Kandorian Thara Ak-Var who had rescued Chris from the Phantom Zone shortly before the Zone began to collapse upon itself. Although only a short time had passed, Chris' unique physiology aged him to approximately fifteen or sixteen years old. Thara knew that the emergence of thousands of Kandorians in the physical world posed a great threat to the planet Earth, and she enlisted Chris' aid to become a costumed, Kryptonian crime-fighter on Earth. Thara and Chris adopted the code names of two legendary Kryptonian heroes, Flamebird and Nightwing. As Nightwing, Chris began actively patrolling several American cities.
After returning to the Phantom Zone, Chris entered the Kryptonian prison where his parents had made shelter. Finding a piece of Brainiac's technology, Chris's mind interfaced with the device, expanding his consciousness, and somehow forging a connection with the mind of Thara Ak-Var, security chief of Kandor, which had recently been freed from Brainiac's ship by Superman. Thara used the connection between their minds to stage a successful rescue attempt with the added help of Non. When the citizens of Kandor created New Krypton, which was placed in orbit around the Sun at the opposite side of Earth, Chris and Thara tasked themselves with the mission of bringing in the Phantom Zone Kryptonian criminals hiding on Earth as sleeper agents. Since the belligerent government of Alura Zor-El and Zod had tarnished all Kryptonians' reputations on Earth, Chris and Thara decided to act as a new Nightwing and Flamebird duo, at first with simple cloth masks, then with fake power suits, to throw people off about the origins of their powers.
However, Chris, due to his birth in the Phantom Zone, exhibited strange and uncontrollable growth spurts: Despite his young age when Thara saved him, as Nightwing he was shown being roughly 15 or 16, and after another debilitating growth spurt, he aged to 23 years old.
His mother, Ursa, stalked him for vengeance. Chris had been shown refusing his heritage, and insisting that Thara address him by his "human" name, despising her attempts to transliterate it as a Kryptonian name, and never going by his birth name of Lor-Zod. After a brutal attack by Ursa, Thara was left gravely wounded by a frangible Kryptonite knife, and Chris was forced to bring her to Lois Lane for medical assistance.
Once he brought Thara to Lois, the two had a tearful reunion; although Lois was happy to see him again, she was concerned about his advanced aging. Lois called Doctor Light for medical assistance while Chris went back to the fortress and was again confronted by his biological mother. Their conflict was cut short as UAVs sent by Sam Lane arrived at the scene, forcing both to flee.
While Chris returned home to Lois, he found that Thara had recovered and was being quizzed by Lois about their relationship. Before Lois was able to learn anything, the two flew away to confront a Kryptonian couple on a crime spree. The four battled, with Chris and Thara quickly gaining the upper hand; however, their fight was interrupted by Codename: Assassin and what seemed to be a gang of "ogres." The sleeper couple used the distraction to escape. Nightwing pursued them, but was forced to let them go in order to save some innocents from a falling bridge.
After the two had received a hero's thank you from a crowd in Hollywood, Thara noticed that one of the girls gave her phone number to Chris. Chris asked if she was jealous, while Thara/Flamebird lied that she did not care if he went around with hundreds of girls. Reacting on an impulse, the two shared a kiss. Before either of the two actually managed to respond they were attacked by Metallo and Reactron and captured.
The Hunt for Reactron Main article: Supergirl: The Hunt for Reactron However, Chris and Thara were teleported away, along with Kara Zor-El. Supergirl attacked Thara for killing her father and trying to kill her. However, Chris stopped her and told her that he was his cousin. The three were attacked by Guardian and the Science Police, for apparently killing Mon-El. Chris tried to tell Guardian that they did not murder Mon-El, but Guardian ignored him. The three managed to escape to Paris where Kara had a safe-house. Chris, Thara and Kara talked about what had happened. They then discovered that the two sleepers they were fighting were Metallo and Reactron. However, they are attacked by Squad K.
Framed for the murder of Mon-El, the two managed to escape from Squad K, and went to Lana Lang's apartment. They decided to get Lois's help in clearing their names. Chris and Lana went to find Lois while Kara and Thara stayed in Lana's apartment.
Chris and Thara were discovered, and once more forced to flee. During the attempt to flee, they once more encountered Squad K: however, the three opted to surrender in order to clear their names. While they managed to persuade the Squad K commander, Reactron quickly murdered his team-mates and attempted to kill the three.
During their conflict, Thara was injured while attempting to protect Supergirl. As Reactron was about to kill Chris and Kara, Thara manifested her Flamebird powers and personality, easily overpowering and defeating Reactron. The Flamebird decided to kill Reactron but was swayed to show mercy after Reactron revealed that Mon-El was alive and Flamebird was further calmed by Supergirl. The Flamebird was fully submerged after sharing a kiss with Chris.
World Against Superman Main article: World Against Superman Donning new costumes, Chris and Thara continued to save lives, despite their actions being twisted by the anti-Kryptonian media. During that time, Thara revealed the history of Kryptonian mythology to Chris via an information crystal encouraging him to deepen his relationship with Thara and engage in sexual union with her.Not long after, Chris experienced another aging spurt, becoming an old man. Doctor Light brought Chris to her colleague, Doctor Pillings, who, unbeknownst to any of them, was the Kryptonian sleeper agent Jax-Ur.
Jax-Ur's theft of Chris's DNA and its purpose was soon revealed as he unleashed a replica of the Kryptonian deity Rao to trample and rampage across Earth. Thara attempted to subdue Jax-Ur and the false deity but even in her Flamebird form, was overpowered. Meanwhile, Chris was helpless, stuck in the Phantom Zone once more, banished there by Jax-Ur. While he was there he could only observe as Thara, Lois and other heroes battled against Rao but failed to inflict any actual damage; only Wonder Woman managing to hold her own. Saddened and frustrated, he was contacted by the Nightwing Kryptonian entity, opposite and lover of Flamebird. Nightwing revealed that while Thara is truly the host of Flamebird, so is he Nightwing's. For some reason, however, the two were unable to connect. Seeing that Thara and the others wouldn't hold out much longer, Chris and Nightwing merged properly and were able to free themselves.
Chris became a fully fledged avatar of the Nightwing entity, and was able to fight Jax-Ur (revealed to be the Kryptonian deity the Builder as well) along with Flamebird on even terms. Furious that Nightwing escaped, Jax-Ur fled into the heart of his construct, Rao, and triggered a self destruct located in Rao's heart which would engulf the Earth into a black hole and rip the universe apart. Nightwing and Flamebird together were able to overpower him, and Nightwing absorbed Rao's heart into the Phantom Zone, where it was rendered harmless, and destroyed the Rao construct. Once the Rao crises was dealt with, both Thara and Chris regroup with the other heroes, kiss, and flee in order to avoid any more hostilities with the locals.
War of the Supermen
Main article: Superman: War of the Supermen During the War of the Supermen, the solar system's sun was turned red by the combined efforts of General Lane and Lex Luthor. Thara sacrificed herself to restore it to its yellow coloration, becoming a charred skeleton. Chris attempted to join her, but the Nightwing entity spirited him away.
In the final confrontation between Superman and Zod, Chris pushed Zod back into the Phantom Zone. Once back in the Zone, Chris became a young boy once more, and encountered Mon-El again