Assassin’s Creed Valhalla is now going into its second year of post-launch content, which kicks off with the franchise’s first two Crossover Stories. These stories see Valhalla’s Eivor meet Assassin’s Creed Odyssey‘s Kassandra/the other guy. How is it possible that a Greek mercenary in 458 BCE could meet a Viking warrior in 878 AD? Well, that’s a pretty major spoiler for Odyssey’s campaign. So if you haven’t beaten Odyssey yet and plan to, turn back now.
In Odyssey, Kassandra (look, she’s the canon protagonist, we’re going to use her name and not Alexios just to make this whole thing easier) discovers she’s the daughter of Pythagoras, an Isu. After helping her father protect Atlantis, Kassandra is given his staff, a powerful Piece of Eden called the Staff of Hermes. Those that hold it are immortal for as long as they remain in contact with it.
Odyssey ends with Kassandra gifting the staff to Layla (the modern-day Assassin protagonist of Origins, Odyssey, and Valhalla) in 2018–revealing that Kassandra has actually been alive through every single Assassin’s Creed game to date, including Eivor’s conquest of England in Valhalla. In theory, Kassandra could have met every Assassin’s Creed protagonist and we just haven’t seen it yet.