Four characters from Eternals were originally meant to appear in Moon Knight, according to the show's producer. Starring Oscar Isaac as Marc Spector/Steven Grant, Moon Knight is the fifth live-action Marvel Cinematic Universe show for Disney+. It debuted earlier this year and quickly caught the attention of viewers for its standalone story, which focused on Moon Knight's alters, Egyptian mythology, and much more. Moon Knight earned favorable reviews based on its focused approach, as the show's cast remained relatively small in terms of Marvel projects. Instead of focusing on an array of known MCU characters, the series introduced Arthur Harrow (Ethan Hawke) and Layla El-Faouly (May Calamawy), giving each of them prominent roles alongside Moon Knight.
Despite the lack of any major MCU connections in Moon Knight, leading up to its release, there was still lots of speculation as to what known characters could appear. In the short time since Moon Knight's ending, it has been confirmed that there were plans for some larger MCU crossovers at one point. Director Mohamed Diab teased that early drafts of the scripts included a few major characters in the first and last scenes of the series. He didn't reveal who Moon Knight's cut MCU cameos were, though, sparking more speculation.
Now, it has been revealed that four cast members from Eternals were originally planned to appear in Moon Knight. During an interview with The Direct, head writer and series producer Jeremy Slater confirmed that he wanted the Eternals to help open one episode. He said he specifically wanted Kumail Nanjiani's Kingo to be part of a quartet of Eternals to appear because Slater and the actor are good friends in real life. The idea was for Kingo and three other unspecified Eternals to appear in a flashback that showed them fighting alongside one of Khonshu's prior Avatars in ancient Egypt. Ultimately, Moon Knight scrapped plans for the Eternals crossover due to how expensive it would be.
I tried very hard to get the Eternals into the show, just because I’m buddies with Kumail Nanjiani… I want[ed] some Kingo. At one point, there was a flashback on the page that sort of showed one of Khonshu’s Avatars back in ancient Egypt, sort of dealing with Ammit being locked away, and Alexander the Great, and all of that stuff. You sort of saw this Avatar team-up with the Eternals. It was a really fun scene, but again, it was so massively expensive to recreate Ancient Egypt, to sort of bring in 3 or 4 of the Eternals to have this big action sequence.
It was one of those things where it was a very fun scene, and it would have been a great cold open to one of the episodes, but it also would have had to come out of our budget somewhere else, and probably would have hurt our finale along the way. So, that was the cameo I had to cut. It hurt, but it was also the right thing to do for the show, and I think everyone sort of collectively agreed. There’s plenty of time in the future to team this guy up with other characters in the MCU and start building these connections; let's not force something just because the other shows have all had it.
The idea of the Eternals appearing in Moon Knight might have been a fun one, but it would also greatly change their history and the context of the show itself. Eternals explained that the superheroes were only allowed to interfere in human events that involved Deviants. An appearance by Kingo and other Eternals would mean Khonshu's prior Avatar helped fight a Deviant and that they attacked ancient Egypt at one point. This could fit within the backstory given to the characters in Eternals, but that is only true if a Deviant was involved in the Egyptian conflict.
Even though the Eternals and Moon Knight didn't cross over in this instance, this could've been a clever way of connecting them both to the larger MCU. It also would surely have been a pleasant surprise to see Kingo and other Eternals characters appear in this setting, as it would further establish their role in protecting humanity. Meanwhile, the Eternals could've been the major MCU cameo that some Moon Knight viewers wanted. The Eternals fighting alongside a previous version of Moon Knight in ancient Egypt would undoubtedly be a surprising way to start an episode, especially if that was meant to be the very first scene of the whole series.
Source: The Direct
