Recently, Star Wars Jedi: Fallen Order fans noticed that there was a hidden skill tree in the background of Cal's meditation menus. Many see this as a positive thing, a branch in which fans will achieve in the sequel that potentially shows Cal rise from Jedi Knight to Jedi Master. Alternatively, and perhaps more speculatively, this hidden skill tree could instead be hinting at the powers of the Dark Side.
Star Wars Jedi: Fallen Order is a Jedi story, which is at least one reason why Respawn Entertainment didn't include choices between the light and dark side. But just as shown by Cere and Trilla, and countless Jedi and Force Users before them, there's no really cutting off the Dark Side in full. Revan, arguably one of the most powerful Jedi in the canon, teetered back and forth. Cal may be a dedicated Jedi, but he doesn't have the training to cut out passion, emotion, and all the things that power the Dark Side. Of course, this is speculation, but one key moment in the game could suggest that fans shouldn't rule out a potential turn for Cal Kestis.
A Jedi Knighted by the Dark Side
During the Dark Times, Jedi had to do what they had to do. Yoda hid away on Dagobah, Obi-Wan Kenobi became Ben Kenobi, Kanan Jarrus became a smuggler, and Cal initially became a Rigger. These may have come about due to necessity, but each was fundamental in the storytelling: Dagobah added mystery to Yoda in the Original Trilogy, Ben Kenobi's legacy lived on (not Obi-Wan's), Kanan's skills translated well to the rebellion, and Cal's hiding means he inevitably gets caught. Each set up more for the story, not always earnest foreshadowing, but sometimes.
As such, though it happened out of necessity, it's hard not to see Cal Kestis being Knighted via a Red Lightsaber as a dark omen. Not to mention, while she seemingly comes to terms with her own pull to the Dark Side, Cere's struggles with it and using a Sith/Inquisitor Lightsaber from Trilla, who was also a Padawan-turned-Inquisitor. Nothing has come of it yet, obviously, but if this is less "cool scene made possible due to in-game necessity" and more foreshadowing for Cal's future, it has some major implications for the next game.
Star Wars Sith: Rising Order
With the unusual naming convention (a colon after Jedi), it's hard to say for sure if the next game will be "Star Wars Jedi: Fallen Order 2." While Cal does seem likely to return as the protagonist, it doesn't have to be either. Whether Cal is a NPC or playable character, opening up the aforementioned hidden Skill Tree in Star Wars Jedi: Fallen Order seems like a no-brainer. How Cal, a devout Jedi, would turn to the Dark Side remains to be seen, and obviously, there's no guarantee it would happen. It would make for an interesting story, if not without its own risks. Every Jedi is tempted with the Dark Side, and most Jedi games revolve around players walking this morality too.
Such a move could risk being derivative; however, that doesn't have to be the case. Seeing Cal tap into the Dark Side but perhaps not surrendering to it could be a great way to introduce Gray Jedi in Star Wars Jedi: Fallen Order 2. Watching a confused, perhaps brainwashed Cal fight to get back to the light would be interesting. Or, perhaps as a new Jedi, trying to bring Cal back to the light like Luke did his father Vader and, to a lesser extent, how Rey brought Ben Solo back from the brink is a story that is timeless...if well executed.
Ultimately, it remains to be seen and this is all speculation. Being knighted by a Red Lightsaber seems like a Chekov's Gun moment, but at the same time, there's really no indication yet as to what Star Wars Jedi: Fallen Order 2 will explore.
Star Wars Jedi: Fallen Order 2 is reportedly in development.