Ubisoft recently confirmed that Assassin's Creed Valhalla would be getting the longest post-launch support of any franchise game to date, and the first major aspect of that is the Wrath of the Druids DLC. While this article may contain LIGHT SPOILERS ahead for the DLC, direct references to any events will not be involved, but it should be said that there's no major lore or world building connected to the DLC.
As unfortunate as that is, Assassin's Creed Valhalla's Wrath of the Druids DLC does have some connection to other AC games if players squint the right way. This includes Assassin's Creed Rogue's Shay Patrick Cormac, as well as more generalized connections to Assassin's Creed Origins, Assassin's Creed Odyssey, Assassin's Creed Chronicles: Russia, and Assassin's Creed Revelations. These connections are listed below with as few details as possible just to discuss their relevancy.
Trials of the Morrigan
In Wrath of the Druids, the Trials of the Morrigan appear around Ireland as a mystery. Notably, though, the name should catch the eye of many fans, as it was also the name of Shay's ship in Assassin's Creed Rogue. Being descended from Irish immigrants, it would seem like a missed opportunity for AC Valhalla to not reference Shay somehow here, and while it could have gone further, it's an immediately recognizable nod. It's not the first, however.
Morrigan is believed to be an Isu who can take the form of a wolf, but in the base game, she's also brought up in name by scripts discovered beneath Stonehenge. Layla eventually gets these translated, though nothing really comes of it. At the same time, Shay directly references Morrigan as inspiration for the name of his ship. Morrigan and "The Morrigan" are both acceptable names for her, but choosing the latter as with the aforementioned shield has to be intentional nods to Shay.
Dublin's Trade Status in AC Valhalla Wrath of the Druids
Looking at the "Trials of the Morrigan" as a reference in name alone, the others come in the form of setting alone. Players are able to establish trade with the world at large from the port of Dublin, and players unlock new locations at certain points. Each of these locations were seemingly cheekily chosen, as each setting connects to one of the games, if sometimes loosely. The Byzantine Greeks are one of the first trading partners and may be a slight stretch. At first glance, though, it's hard not to think of Assassin's Creed Odyssey because of its Greece setting. However, the Byzantine Greeks considered themselves Roman, which is the setting of AC: Brotherhood. However it's looked at though, it's pointing to a connection somewhere.
Wrath of the Druids players will also unlock Egypt as a trading partner, with the associated armor looking exactly like something Bayek or Amunet would wear in AC Origins. It, alongside Constantinople, are the more clear nods to past games. Fans may recognize this location as the one where Assassin's Creed Revelations, Ezio's last game, takes place. It may be a somber nod, but at the very least, it guarantees a nod to the beloved protagonist.
Finally, there's also trade with the Rus. Now, this one is interesting because rumors once indicated AC Valhalla would have included the Kievan Rus, but that was a stretch then. It would be interesting to see proper game set here, but nonetheless, it operates as another indirect connection, to Assassin's Creed Chronicles: Russia this time around. Both Belarus and Russia claim the Rus as their ancestors, adopting part of that name into their own. It doesn't take place in the same area as the Rus occupied, at least it seems, but there's a line that can be drawn here for the Russian game.
While some of these seem like bigger stretches than others, the inclusion of areas like Egypt and Constantinople seem more intentional than not. Either way, while it adds very little to the overarching lore of Assassin's Creed Valhalla, it is a nice nod to past games.
Assassin's Creed Valhalla's Wrath of the Druids DLC releases May 13 for PC, PS4, PS5, Stadia, Xbox One, and Xbox Series X.