Star Wars: The Rise of Skywalker introduced Richard E. Grant as Allegiant General Pryde - but who is this mysterious new leader in the First Order? The First Order has always been a secretive organization, with information strictly compartmentalized between different divisions. Even high-ranking officers were unaware of the true scale of its forces.
Kylo Ren's leadership style, however, is very different to Supreme Leader Snoke's. He has abandoned the traditional secrecy, instead establishing a clear chain of command with the Supreme Council at their head. The Supreme Council act as Kylo Ren's closest advisers, and they include the First Order's most experienced and valued leaders as well as their closest aides. One of their key members is Allegiant General Pryde, a suspicious Imperial veteran who holds a unique rank and station.
According to the Star Wars: The Rise of Skywalker Visual Dictionary, Enric Pryde was born on the planet Alsakan shortly before the Clone Wars. He welcomed the strong hand of the Empire, and was trained at the Imperial Academy on his homeworld. A fascist at heart, Pryde was fiercely loyal to the Empire, and he fought on after the Emperor's death in Return of the Jedi. He was one of a small number of Imperial loyalists who escaped Jakku in order to travel to the Unknown Regions, where they founded the First Order. Pryde knew more about Palpatine's machinations than many of his fellow Imperials, and he used that knowledge to cement his own power.
Pryde seems to have been one of Supreme Leader Snoke's closest backers, and he worked alongside Armitage Hux to establish the First Order's Stormtrooper program. Snoke granted him what appears to be a unique rank in the First Order, "Allegiant General," which seems to be roughly analogous to a Grand Marshall in that he commanded both ground and space-based military forces. Snoke held Allegiant General Pryde in reserve during his initial Blitzkrieg across the galaxy in Star Wars: The Force Awakens and Star Wars: The Last Jedi.
Pryde has always had a degree of respect for the Force, having once witnessed Darth Vader in action. As such, while he doesn't share the ideals of the Sith and cannot be considered one of their cultists, he believes they have their place in the First Order. According to the Visual Dictionary, Kylo Ren never revealed that he was the one who killed Snoke, but Pryde seems smart enough to have suspected as much. When he learns that Palpatine is back, it's frankly no surprise that Allegiant General Pryde decides that his loyalty lies with the Emperor.