Although nothing has been confirmed by Ubisoft about Assassin's Creed Ragnarok, all current evidence points toward it being the next game in the franchise. From in-game teases in The Division 2 to high-profile corroborations of its existence, it seems safe to say that fans next trip in the Animus will be to the Viking Era, set between Assassin's Creed Origins and the original Assassin's Creed. However, this should not be a surprise to eagle-eyed fans of the franchise, as it has been teased even before 2019, and there's one man who ties all of this together: Otso Berg.
Juhani Otso Berg is a Master Templar who has been explored thoroughly throughout the comics, but for the majority of the franchise games, he's been a character in the background. First introduced in Assassin's Creed Rogue, Berg plays a role in the main storyline and then also later appears at the end of Assassin's Creed Odyssey's DLC run. Each appearance, as well as some facts from the character's life, all point toward Vikings in Assassin's Creed Ragnarok and suggest his role will be bigger than in previous games.
First, since he comes from southern Finland, it's easy to deduce that his heritage is geographically close to the Viking area said to be explored in Assassin's Creed Ragnarok. It is worth mentioning, though, that Vikings had little contact with Finnic people, but his family may have very well been one of those to have contact, as in-game audio files reveal that one of his ancestors was a Viking raider.
It seems Berg used an Animus once to view his ancestor, discovering and being disturbed by his ancestors actions: "It was summer. Good sailing weather. The monastery was a center for religious studies, and we crashed into the city like a tidal wave." This was determined to be the Viking raid on Lindisfarne in 793, where his ancestor would defeat a Saxon Warrior, offer him the chance to join the Viking clan, and then killing him after being refused.
Recent Assassin's Creed: Ragnarok rumors have suggested that the game would cover the earliest years of the Viking Era (which traditionally lasted from 800 to 1066), meaning that this memory coincides with rumored time frame of the next game. As such, it would be interesting to see how and if this memory would be involved, and if this unnamed Viking Raider actually turns out to play a big role in the game, perhaps even serving as an Assassin in a poetic twist of fate.
However, there's more that could come from that, but the evidence of Otso Berg's role in the next game does not end there. It's long been noted that Berg's attire in Assassin's Creed: Rogue is highly reminiscent of the primary protagonist, Shay Cormac. The Assassin-turned-Templar was born of Irish immigrants, placing his ancestors in a similar geographical location as Berg's ancestors and a close proximity to whereabouts of Assassin's Creed: Ragnarok.
Furthermore, Shay bore Nordic symbols such as that of Yggdrasil and triquetras, with Berg himself also adorning himself with the symbol of Yggdrasil. This could mean nothing, or it could be suggesting that Berg and Shay are closer than many think, with perhaps Shay being an ancestor of Berg. These could easily be jumping off points for the main section of Assassin's Creed Ragnarok, but what about the modern Assassin's Creed storyline?
At the end of Assassin Creed Odyssey's Fate of Atlantis DLC, Berg is severely wounded by modern day protagonist, Layla Hassan. It wouldn't make a lot of sense to leave him there to die, so there's a good chance that Berg has been captured by the Assassins prior to Assassin's Creed Ragnarok, which sets up the perfect way to explore this period with a man whose Ancestors lived during it.
This is mere speculation, but it stands to reason that the Assassins could sequence Berg's DNA to relive memories of his ancestors, allowing players to explore his/her story of the Viking Era. It could also just be that his ancestor is encountered during this time period, and he serves as a sort of "live-in expert" on the Viking's role in the greater Assassin-Templar conflict. However, if the first one were the case, it could potentially set up the perfect character arc between Berg and Cormac.
Cormac discovered the follies of the Colonial Brotherhood, turning his back on the Assassins and joining up with the Colonial Rite of Templars. Berg is currently a figure known as the "Black Cross," who holds two primary responsibilities: investing the Templars to ensure that the organization's codes and ideals are being upheld and track the various Pieces of Eden. It would a full circle instance of poetic irony if, during the course of Assassin's Creed Ragnarok, Berg discovered a major Templar secret that saw him turn to the Assassins instead - a full about-face from Cormac's path.
Of course, there's still a ton of unknown variables about the next Assassin's Creed game, and whether or not Vikings are involved is still unconfirmed. Yet, assuming that they are and assuming that Otso Berg's final appearance in Assassin's Creed Odyssey doesn't turn out to be anti-climatic, then it seems safe to say that there will be some sort of connection between Berg and the Viking protagonist. After all, ancestry and familial relations is as much an Assassin's Creed core concept as the overarching conflict and the first civilization, so it would be surprising to see so much character history be built up over the course of the franchise, just to be snubbed when it can possibly all come together. As it stands, though, fans of the franchise will have to wait until Ubisoft officially reveals Assassin's Creed: Ragnarok.
Assassin's Creed Ragnarok is rumored to be in development.