Disney always uses characters or events from the books and games of Star Wars to introduce them into the official canon. That's what happened to Darth Revan from Star Wars: Knights of the Old Republic.
Grand Admiral Thrawn from the trilogy by Timothy Zahn (1991 to 1993) was brought into the Star Wars canon with new novels after Disney described all books, comics and games as "unofficial". But more and more characters and events from these "Legends" novels are gradually finding their way into the official canon. These include the Holocrons or the Czerka Corporation.
Darth Revan is an official part of Star Wars
Now Darth Revan is out too Star Wars: Knights of the Old Republic official part of Star Wars. The Sith Lord, who lost his memory and who you then embodied in the game, borrows his name in Star Wars: Episode 9 – The Rise of Skywalker to a Legion Sith Trooper – the soldiers are part of the 3rd: Revan Legion. Darth Phobos and Desolous from the "Star Wars: The Force Unleashed" games also appear as names for legions. This emerges from the official book accompanying the movie, in which the troops get their names.
It is quite possible that this could also be an indication of an upcoming Star Wars film, because there is allegedly a film in the works that takes place in the time of the Old Republic.
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