While it has not yet been confirmed how Walter factors into the story, it appears to be clear that he will be a member of the crew onboard the Covenant ship, helping out captain Danny McBride and potentially co-captain James Franco as well. Now that more information has been unveiled as to how Fassbender’s roles differentiate themselves from one another, it should be interesting to watch how each is similar in nature as well.
Walter sounds as though he will serve more of a typical role for a robot, following orders and such, which should be a far contrast for David. Hopefully, Fassbender is still able to bring some level of emotion to Walter to make him a likable character and not take a backseat to his counterpart. However, that may be unlikely given David’s repeatedly showing a desire to do as he wants more so than listen to others. This brought David into many interesting, yet dangerous, situations in Prometheus, and his evolution from then till the events of Covenant could be a major focus for his character.
For now, fans of the property and Fassbender will have to wait until a trailer to figure out just how different Walter and David are. But multiple roles should point to even more screen time for Fassbender, which if he has proven anything in the past, should be to the benefit of the movie.