Crimson Empire is sort of the follow-up to the Dark Empire storyline, but it’s focus is a bit different. Although dealing a bit with the chaos after Palpatine’s “final” death in that series, it also pretty much ignores Luke, Han and co, instead focusing on one of the last members of the Imperial Royal Guard-Kir Kanos- who has discovered that the Emperor’s clone degeneration was the result of the tinkering of a fellow Guardsman-Carnor Jax, who has ambitions to lead the Empire-and also has some limited force ability as well. CE was released as three limited series over the course of a few years. The series also dealt in part with how the Royal guardsmen-who first appeared in “Return of the Jedi” and later would appear in the prequels (Where they beaten pretty badly by Yoda in one scene)-were trained.
The initial one had Jax work with a local Rebel cell, who don’t find out his past until later on, but welcome his assistance as they have a mutual enemy with the Imperial remnant. He also forms a relationship with local commander Mirith Sinn (although her Trandoshan ally Sadeet doesn’t trust him).
Kanos and Carnor Jax then have one final battle on the planet of Yinchorr, where the royal guard were trained. He kills Jax, but also Sadeet when he tries to stop the execution of who he felt would be a valuable prisoner, with Sinn vowing to avenge her fallen friend.
The next installment, Council of Blood, has Kanos take on the identity of Kenix Kil, a bounty hunter, and works for a Hutt while trying to get to the Imperial ruling council, of whom one of the members-Feena D’Asta-is a clone, with the original D’asta imprisoned by the Hutt.
He also runs into Sinn again, and saves her as well, beginning a sort of romance. The whole thing is a conspiracy of sorts to weaken the Empire by an alien species; the Yuzzhan Vong, who are manipulating things behind the scenes-specifically, their advance agent Nom Anor. Both Anor and his species will face the New Republic on a much wider scale in the later New Jedi Order book series. Eventually the council is defeated by the new Republic, and it’s leader executed by Kanos.
However, Kanos still has one more enemy who he feels is responsible for the death of the Emperor: Luke Skywalker, of course, and Crimson Empire III brings Kanos into the orbit of Luke, Han and Leia, as well as Boba Fett.
However, it turns out his relationship with Sinn, and his growing disillusionment with the Empire, has caused Kanos to rethink things, and he teams up with Luke and the New Republic to take on a rogue Imperial faction, who are trying to damage a possible Imperial/Republic treaty (By this point in time, apart from some hangers-on many factions of the Empire were kind of more moderate than in the days of the Emperor and Vader-for example, Admiral Palleon-Thrawn’s second in command in the Thrawn trilogy-who would eventually become a ‘good guy’ of sorts by forming a lasting peace a few years later.)
At the end of the series, Kanos is presumed dead, but actually survived and starts a new life, discarding his guard robes. However, any possibility of a future sequel is kind of out of the way now, as the year CEIII was published (2012), Star Wars was sold to Disney who in 2014 largely dropped the previous novels/comics/games’s “canon”, or continuity to build their own. (with a few exceptions). Although a few elements of the old Expanded Universe have been reworked into the new stuff, so perhaps we’ll see Kir Kanos again one day…