The history of the Kingdom Hearts storyline is a long and complex collection of epic character moments and retroactive rewriting. Now with a new title announced, Kingdom Hearts 4 can reset the series and bring back older storylines that have since been abandoned.
One of these abandoned storylines that had previously added a level of depth and nuance to the series is the way that the character Riku had dealt with the power of darkness. However, Kingdom Hearts 4 now has the chance to bring back the original direction that Riku had been taking since the very first game and continued all the way through Kingdom Hearts 2.
Riku's Original Dark Path
When Riku was originally introduced to players in the very first Kingdom Hearts title, he took on the role of protagonist Sora's rival and a consistent enemy into the late-game. Not only had Riku become a pawn of the darkness, the force of evil in the series, but he had also learned to use its power for himself and even crafted a dark keyblade with the help of Ansem. From there, this history with the darkness became one-part stain and one-part benefit for Riku, as he was able to use this power in order to help Sora throughout Kingdom Hearts 2 and retroactively in 358/2 Days.
By the time Kingdom Hearts: Chain of Memories came around, Riku was even given his own storyline that emphasized his reliance on this power of darkness. In fact, it was only by using this power that Riku could temporarily use the sleight abilities to the same degree that Sora was able to use due to his own power of light focused through the keyblade. At the end of this storyline, and into the beginning of Kingdom Hearts 2, Riku outright claims to be taking a path that doesn't choose one of these forces and picks both the light and the darkness.
Riku's Retcon From Dream Drop Distance and On
When Kingdom Hearts 3D: Dream Drop Distance launched in 2012, it had been seven years since the story of the released games had focused on Sora and Riku, then it would be another seven before Kingdom Hearts 3 launched. In that time, a lot of characters got new motivations before the end of the Xehanort saga, including the villain himself who transitioned from "bringing balance" to "recreating the world" between games. Riku was no exception to this trend of shifting alliance and motivation, as he completely abandoned the power of darkness once he got his hands on a functional keyblade.
From Dream Drop Distance and on, Riku was suddenly only a fighter of light, allowing him to be one of the seven pure lights needed to fight against the Real Organization XIII in Kingdom Hearts 3. The result is a Riku who changes by Kingdom Hearts 3 from having embraced his past mistakes to one that moved beyond them. It's a type of character growth that makes sense for a series that is trying to create a stark divide between light and dark, but some fans have seen it as a turn for the character.
How Kingdom Hearts 4 Could Return Riku to a Nuanced Path
In the transition from the familiar worlds of Kingdom Hearts into the new Quadratum setting of Kingdom Hearts 4, the series has more opportunities to redirect characters than ever before. This new Realm of Fiction could painstakingly explain, or more likely hand-wave, new directions as a result of the transition into this new scene. So, with Xehanort gone and the specific need for seven lights and thirteen darknesses disappearing with the villain, Riku has room to continue his struggle between the two forces that move the world.
Along with this new location, the next game is expected to be a new start for the series, with Kingdom Hearts 4 telling a new story unlike anything seen before. In that case, this next game likely won't be the last in the series, and there may be another twenty years ahead of this leg of the series. This means that there will likely be more than one game to continue exploring the depth of the powers of light and darkness working together. The change could especially work if some fan theories about the Master of Masters as a future villain from the light turn out to be true.
Why Roll Back to an Older Storyline?
It could easily be said that focusing on an older storyline might be an unnecessary step back for the series, especially with Riku having already been proven to have moved beyond the need for the power of darkness. However, the reason to return to this arc for Riku is that it never had a satisfying conclusion by the time he had all but abandoned the darkness in Dream Drop Distance. At that point, the character had moved from being torn between two warring worlds to simply going along with the heroes because the plot demanded it. The whole storyline has left the Kingdom Hearts series with a lingering question about the morality of the light and the darkness.
Bringing back this darkness character arc for Riku could finally give a truly satisfying conclusion to his growth that had been foreshadowed in the older titles. As it stands now, this whole section of Riku's development appears to have simply been forgotten, not explored. With Kingdom Hearts 4 bringing back old features, it shows that the older concepts from older games can still have a space in the new direction the series will be exploring.
A Twilight Riku Could be the Key Against the Master of Masters
The antagonist in this new series of Kingdom Hearts titles still hasn't been announced, even if there already have been several reveals from the Kingdom Hearts 4 trailer. However, after the secret ending reveals from Kingdom Hearts 3 and Union X, many fans believe it will be the mysterious Master of Masters who has been pulling the strings even beyond Xehanort. Additionally, this possible antagonist's motives have also been made perfectly clear through the final few scenes in Union X.
If this is the case, then taking Riku's history of using both light and darkness could put him in the perfect position to counter the Master of Master's position of undying hatred for the beings from the dark realm. So, Riku living in the middle ground between both realms could act as an example for why the Master of Masters is wrong. It could lead to a way of defeating a Kingdom Hearts antagonist by actually reaching through to them, rather than just hitting them with a keyblade until their health bar is empty.
Kingdom Hearts 4 is currently in development.