The New Sun is native of Earth-9923 and is an alternate Gambit, but unlike Gambit, the New Sun was never adopted by the Thieves Guild, so his real name is not "Remy LeBeau". His powers grew unchecked even after he was found by his world's X-Men. He managed to stop an incarnation of Dark Phoenix. New Sun was raised with his full power and intended to become the fulfillment of an ancient Guild prophecy to create Heaven on Earth. However instead, when he charged up his power in a special ritual, a chain reaction was started that caused everyone on Earth beside himself to burn up. Failing to remake time, the New Sun traveled to other universes, hoping to prevent the same thing from happening there. However, he found many worlds in ruins, often because of that world’s version of Gambit. Coming to the main Marvel Universe, he first attempted to create a new world where everyone would eventually be transported to, using the main reality’s Gambit to help (without revealing to him who he truly was). When he learned that his plan wasn’t possible, he tried to kill Gambit, transporting both of them to his destroyed home world before he became a threat to the main universe’s Earth world as well. During their final conflict, Gambit finally blasted the New Sun, burning out his recently increased powers, just as the New Sun died.
The New Sun parents were paid to have a kid for their genetic potential. The child was raised by Alpha-1 and trained in the use of his powers even before he had them, so that by the time they manifested, he was expert in their use. So much so that he destroyed the Alpha-1 facility and flew off. He joined the X-Men for a while but left after killing that reality's Phoenix. Though he operated as a solo hero afterward, he never felt comfortable with the other heroes. Then he met Jean-Luc LeBeau, who told him of the legend of the restoration of the Old Kingdom, which he, as "Le Diable Blanc," the white devil with red eyes, was fated to accomplish. Together they prepared for the restoration, digging into a mountain in Turkey where a statue of the last King was buried. The ceremony worked exactly as prophesied - unfortunately. The combination of mystical and kinetic energies created a shockwave that destroyed all life on the planet - except the mutant who started it. The "New Son," as he now called himself, tried to use his powers to manipulate time and undo his deed, but ended up accessing the Spiral of Worlds, a gateway to the multiverse. There he found worlds upon which there were other versions of himself, and he vowed to never let what happened to his world happen to another. He came to our world (Earth 616) and sought out Gambit, his counterpart here, and found him just after the X-Men stranded him in Antarctica. New Son helped Remy escape the South Pole, and then sent him and Courier on a mission to the Savage Land . Even after Remy rejoined the X-Men, he was still running errands for the New Son, including stealing a database of all mutants from Muir Island and getting some mind-controlling gas from a Japanese mutant boy, among other things. New Son also had Fontanelle dreamscape various people close to Remy and connected to Black Womb (our version of Alpha-1), hoping to learn more about his doppelganger. New Son's plan was to move everyone on Earth to a new planet created exactly 180 degrees away on Earth's orbit, but that plan was scrapped when Dr. Doom brought the " Heroes Reborn" Earth to that location. The New Son then shifted his focus, using the mutant known as Quiet Bill to scour the multiverse for timelines in which Gambit died before destroying the world, as well as ones where he lived. He then hired a number of assassins to kill Remy, though the purpose of that game was actually to force Remy to use his newly expanded powers to their ultimate potential. He even dressed up as the X-Cutioner II (using a version of the X-Cutioner's armor), in order to confuse Gambit. Then New Son revealed himself to Remy, showing him that they were the same person from different realities. Remy was not amused, and freed Quiet Bill and his pal Huey and trapped New Son between moments in time for a while. New Son escaped, and realized that his name should be "New Sun," a testament to the prophecy about the resurrection of the Old Kingdom, which would "bring all into the light of a new sun." Finally, the New Sun broke into Gambit's safehouse, attacked Huey and commandeered Quiet Bill's power to transport Remy to his own ravaged world. There New Sun told his story and then attacked his counterpart. Gambit finally accessed all of his power, but the New Sun's experience proved far too much for him to handle. The fight took them to the site in Turkey from where New Sun had destroyed the world. New Sun grabbed Remy, who poured all of his vast energies into New Sun, overloading his system. The tremors shook the statue of the ancient King, which fell and impaled New Sun on its spear. New Sun exploded, along with his world. Gambit was pulled back through Bill's portal just in time by Courier.
New Son had control of kinetic energy at a molecular level. He could turn an object's potential energy into kinetic energy, making it explosive. He does not need to make physical contact to do so, nor does he have a block to prevent him from using this on a living being. He can cause another being to be unable to move or unable to stop if in motion. He was able to cause or simulate various energies by manipulating the kinetic energy present, such as infrared and microwaves by increasing molecular agitation, or cold by reducing it. Lastly he could transform himself into an energy wave to travel through space and into other dimensions.