If you've played all of the Assassin's Creed games, you'll notice a strange trend. Many of the most popular games in the series did not feature the Assassin's guild as prominently. Since Black Flag, Ubisoft has moved the guild into the background.
However, Assassin's Creed: Valhalla seems to be breaking away from this trend. In the game, the player encounters the templar (order of ancients) and assassins (hidden ones) from an outsider's perspective. In this way, Ubisoft may be trying to bring back the assassins in Assassin's Creed.
How Black Flag changed Assassin's Creed
Black Flag is the first game in the series where the player is not an assassin until the very end. The player is a pirate, so they don't need to follow any particular creed. Edward Kenway works with the assassins and occasionally hangs out with them, but he's his own man.
This isn't the case with Unity, but Unity was in development long before Assassin's Creed 4 was released. Assassin's Creed: Unity (2014) was released one year before Black Flag (2013), so feedback from Black Flag would not have applied to Unity. The guildless pattern really takes hold when you move onto the next game.
The protagonists of Assassin's Creed Syndicate (2015) are assassins, but they are sent to a city where assassins are almost extinct. Are the protagonists considering rebuilding the order? Instead, you form a gangster coalition, The Rooks, to retake the city.
In Assassin's Creed Origins (2017), the player meets the founder of the Assassin's Guild before he founded the order. Even though the game is supposed to be about the origins of the guild, it never really gets to touch on it. The player cannot even see the formation of the assassins (Hidden Ones) unless they buy a DLC.
Assassin's Creed Odyssey (2018) even goes further back to the Peloponnesian War. At the time, there was no guild. We see the precursor to the Templars, but they have nothing to do with the assassins at all. Although we can find the hidden blade in the DLC, it's just an offhand way to refer to assassins in an Assassin's Creed.
Is Assassin's Creed: Valhalla different from the other games?
A unique aspect of Assassin's Creed: Valhalla is its early introduction to the Hidden Ones. From Black Flag onwards, every other game (except for Unity and Rogue) has tried to hide the player's affiliation with the assassins. In Assassin's Creed: Valhalla, the player helps the Hidden Ones establish a foothold in England.
Ubisoft has often said that it has heard players' feedback about many things, but it is a bad idea to bring the guild back all at once. It makes more sense to give the assassins more of a role like they did in Assassin's Creed: Valhalla.
As far as I can tell, the next Assassin's Creed will play a more significant part in the guild's development. Following it will be an Assassin's Creed game that features the guild in all its glory.
It may take a few months, but we'll find out when the next game is announced.