I was surprised to see that Abstergo was not even a presence in AC Valhalla, as it had been in the last two installments. spoiler

It would have been super cool if the ‘employee’ you played as in AC Rogue became a significant threat to the Assassins in the present day during the Valhalla storyline, as that person would have ‘acquired’ necessary skills from being Shay Cormac. Also in Rogue, Juhani Osto Berg even noted that he had seen his Viking ancestor participate in the raid at Lindesfarne, so there could have been some connection to a later descendant that would have been around during Eivor’s time. That Abstergo-Shay figure would have peered into Berg’s Viking ancestry to see something that hasn’t been discovered through Eivor’s memories... something that Berg would not have had the context to understand previously, but which would be relevant now given the Assassin interest in Eivor.

I consider it a missed opportunity, but Ubisoft still has a chance to bring that person back into the narrative and make things very interesting for the story in any upcoming expansions they have planned for Valhalla.