Little is known about the Nightcrawler version of the Mutant X universe. Having stayed with Magneto's X-Men even after several members quit to form their own group, the Six, Kurt sported some devil-may-care attitude and tended to disobey direct orders. A swashbuckler through and through, even his costume evoked the old Errol Flynn pirate movies he loved so much. The X-Men's lineup also included Mystique and Rogue, but it was left unclear what, if any, relations Kurt had to them. Nightcrawler died alongside most other heroes of this Earth when they fought the combined threats of the Beyonder, Dracula and the Goblin Force.
A unique twist in the Earth X reality led Kurt Wagner to become the X-Men's old nemesis, Belasco. Working with Excalibur, Kurt lost his arm following an attack by the Grey Gargoyle and, in a tragically ironic twist of fate, was turned back into a normal human appearance. However, the general populace having been mutated worldwide when the Inhuman Terrigen Mists were released into Earth's atmosphere, Kurt was again an outsider. Nightcrawler was now hunted down for looking "normal" by a mob altered to look "different." Thanks to the machinations of Mephisto,
he was re-mutated into a new demonic appearance, his memory fogged, and he replaced the true sorcerer Belasco in Pangea just in time to be reawakened by Shanna O'Hara. So, the man who hounded the X-Men, tormented Ka-Zar, and corrupted Colossus's sister Illyana was none other than their own friend and time-displaced teammate. Nightcrawler eventually regained his true memories and identity and began living in New York City, replacing Daredevil as the devilish protector of Hell's Kitchen.
In the Ultimate universe, Kurt Wagner, was an innocent German teenager who was captured by the Weapon X project and forced to become one of their mutant agents. However, they couldn't beat his idealism out of him, for even as Storm sought vengeance against the Weapon X commander, John Wraith, Nightcrawler stopped her from becoming a killer to prevent her sinking to Wraith's level. Kurt returned to his native Germany, but later joined the X-Men, when they needed help against Magneto and has since attended Xavier's school. A friendly, humorous young man with a zest for high adventure, Kurt was initially well-liked among his teammates. He somewhat bonded with Angel, the only other X-Man besides him who could not hide his mutation, and together they "misused" the Danger Room for Pirates of the Caribbean-style role-playing sessions. He was somewhat saddened when Warren found a significant other in Dazzler. 
When his friend Colossus came out of the closet, Kurt had a hard time accepting he was gay, and acted cruelly toward him. Meanwhile, his obsession with Dazzler deepened so much that, in a bout of isolation from the X-Men, he kidnapped her. The X-Men caught up with him, defeated him and rescued Dazzler. Professor X placed Kurt into a coma so he could heal his mind. When Xavier disappeared, however, Kurt woke up, escaped from captivity and joined the Morlocks, eventually becoming their leader. After Sinister massacred the Morlocks, Kurt joined back up with the X-Men and made amends. He was killed when Magneto's ultimatum wave struck New York City.
Nocturne of the reality-hopping Exiles comes from a reality called Professor W's X-Men, where time is about 20 years further along than in the main universe. In this timeline, her father Nightcrawler fell in love with and married Wanda Maximoff, the Scarlet Witch of the Avengers. 
The status of their marriage as of Nocturne's "present" and their living arrangements are unclear, since both Nightcrawler and Nocturne were active members of the X-Men while Wanda was still serving with the Avengers. Kurt is the team's field leader in this reality, where a crazed Wolverine killed Professor X and a distraught Cyclops has turned against the group following the deaths of his mentor and his love, Jean Grey. This Nightcrawler has lost an eye at some point, and is far more serious than he was in his younger, swashbuckling years, due to the responsibility of leadership, compounded with overseeing his own daughter's safety in the field. Although his reaction to his daughter's sudden disappearance has not been shown, he probably didn't take it lightly.
When the Scarlet Witch rebuilt reality into the House of M, Nightcrawler was reborn as a member of S.H.I.E.L.D.'s elite Red Guard, alongside Rogue and his mother Mystique. Although this strike force was led by Wolverine, they had to hunt down their leader after he went AWOL upon learning the truth about their distorted reality.
In this timeline postulated in X-Men Forever (2nd series), the X-Men discovered that mutants suffered from "mutant burnout," i.e. premature death, through the overuse of their powers. However, Mystique proved immune to the burnout, as did her offspring, including Nightcrawler. In order to protect her beloved foster daughter as well, Mystique set events in motion that caused Rogue and Nightcrawler to swap powers permanently, thus giving both of them immunity to burnout. 
As a result, Kurt reverted to a normal-looking human with Rogue’s absorption powers. Relatively inexperienced with his new abilities, Kurt fell into a coma after absorbing Thor's powers and nearly died. Mystique and Rogue teamed up with Thor and Danielle Moonstar to travel to the Norse realm of Valhalla to save Kurt from certain death.
Ten to fifteen years in the future, when the X-Men faced The End, Nightcrawler had married Kymri from Earth-1289. Together, they had two children: a girl named Cerise and a boy named TJ. Still a member of the X-Men, he and Jean Grey managed to free that reality’s Nocturne from the Hound conditioning imposed on her by a slaver. After teaming up with the rest of the X-Men to stop the galactic menace of Cassandra Nova, Kurt adopted Nocturne as a daughter of sorts and brought her into his family.
Although life in his home dimension was Utopian for most people, young Kurt Waggoner still endured abuse and bullying at the hands of his peers because of his appearance. A prodigy in quantum physics and robotics, Kurt was just a boy when the machines of his world rose up and declared war on the humans, slaughtering them all. 
Kurt only survived because his parents tranquilized him and hid him with a cloaking device. Sometime after the revolution, Kurt was plucked from his native dimension and imprisoned by a man called the Savior, who was using mutants from across the multiverse as batteries to save his home planet. With the help of his fellow prisoners, Emmeline Frost-Summers, General Howlett and the Cyclops of universe 616, Kurt managed to escape from the Savior and flee into the timestream. Shortly thereafter, he, Emmeline, Howlett and the Dazzler of universe 616 began a reality-hopping quest to rid the multiverse of ten evil Charles Xaviers hell-bent on destruction. During their travels, Kurt got to visit his home world again, where he learned that his parents had died during the revolution at the hands of Danger, the world's new ruler. Angered, Kurt bombed the robot city of Cupertino, California in retaliation. Later, Kurt and his peers succeeded in ridding the multiverse of the evil Xaviers, but in the process, helped rip a whole in the spacetime continuum that allowed a trio of ancient, destructive beings called the Exterminators to escape. With the fate of all existence on the line, Kurt Waggoner was one of the many who bravely sacrificed his life to contain the threat they posed.