<p>
Valkyrie- She was last seen on the Statsesman ship as all the Asgardian refugees fled their homeplanet before Ragnarok was enacted, thus destroying the realm. However, she was not spotted in Infinity War. Thankfully, the Russo Brothers and Tessa Thompson herself confirmed that Valkyrie survived both the Attack on the Statesman and the Snap. What's more curious is that Thompson reported that her character is "well in one piece, and thriving." Sounds like a confirmation. Additionally, she was spotted filming for the Infinity War set at St. Abbs in Edinburgh, Scotland and at the Durham Cathedral. For those who are worried that those were cut for Infinity War, well the Russo Brothers have misdirected fans and I doubt that they would spend massive amounts of money and time just to misdirect Marvel fans. It is extremely likely that she will appear.</p><p>
</p><p>
Nakia,
Ramonda &
W'Kabi- Two other characters who were noticeably were not in the film were Nakia & W'Kabi. W'Kabi's absense is understandable given that at the end of Black Panther, he was presumably incarcerated for his complicity in aiding Erik Killmonger (another character whom I'd love to see return in Endgame). Nakia and Ramonda were both left alive at the end of Black Panther, but they also did not appear in Endgame. Because Infinity War killed off half of the Wakandan population, including Black Panther, and since Shuri's fate was left uncertain, it would make sense if the three supporting characters returned, since they were the most prominent characters in Black Panther who did not die. A Marvel producer mentioned that Nakia and W'Kabi's storylines were not forgotten and will be addressed soon. Furthermore, Russo Brothers stated that she (Nakia) was on an espionage mission in an unidentified country. It is safe to assume that these three characters will likely have a small appearance in Endgame.</p><p>
</p><p>
Red Skull- Since his curse waned after Thanos obtained the Soul Stone, the Red Skull is apparantly free to pursue an Infinity Stone and return to his old goals. Even if Red Skull does reappear in A4, I highly doubt that he will rebuild HYDRA. However, it is extremely possible he will return, perhaps in a flashback or he may even pose as a villain. Who knows?</p><p>
</p><p>
Kaecilius,
Karl Mordo, other
Masters of the Mystic Arts- Since Avengers 4 is dealing with time traveling and since the executive director of Avengers: Endgame confirmed that Tilda Swinton will reprise her role as the Ancient One in the movie, it is possible that, since Mark Ruffalo mentioned to have previously worked with both Tilda Swinton and Cate Blanchett, Hulk could travel to Kamar-Taj and encounter some affiliates of the Masters of the Mystic Arts, such as Kaecilius or Karl Mordo. Apparently, someone filming a scene for Avengers 4 reported Mads Mikkelsen as part of the cast. Although this is unlikely, we can expect at least a few members of the Masters of the Mystic Arts to appear in Avengers: Endgame.</p><p>
</p><p>
Jane Foster,
Erik Selvig,
Darcy Lewis- Jane Foster has been absent from the MCU ever since her appearance in Thor: The Dark World. When asked about her fate, the Russo Brothers refused to reply, saying that her fate was too spoilery to reveal. Suspicious and interesting. Natalie Portman hasn't ruled out the opportunity of reprising her role as Foster. Since Thor will probably not survive Endgame, this will be the best time for Jane Foster to appear in the MCU. Furthermore, a recently-produced Marvel novel corresponding to Avengers: Infinity War featured Jane Foster, Erik Selvig, and Darcy Lewis investigating the Snap. Since the Quantum Realm is a contributing factor to the ultimate defeat of Thanos, Jane Foster, Darcy Lewis, and Erik Selvig could possibly help build a machine that connects to the Quantum Realm, since both Hank Pym, Janet van Dyne, and Wasp disappeared during the Decimation. </p><p>
</p><p>
Korg &
Miek- Two supporting characters from Thor: Ragnarok who were also absent from Infinity War were Korg & Miek. Since then, one of the executive directors of Avengers: Endgame reminded fans to keep Korg in their prayers. Wow, he is possibly alluding to Korg's death. But, it is extremely possible that these two are in one piece and are with the surviving Asgardians, such as Valkyrie. Kevin Feige also confirmed that Marvel has big plans for Korg and Miek. It is safe to assume that Korg, Miek, and other members of the Sakaaran Rebellion will make some cameo in the film.</p><p>
</p><p>
Ghost &
Bill Foster- These two Ant-Man & The Wasp characters could return because they were presumably left alive at the end of the film, and Bill Foster had knowledge about the Quantum machine. Building a second Quantum device could also allow Ghost to channel quantum energy through her body to further cure her from her condition.</p><p>
</p><p>
Hela- As she is the Goddess of Death, she can't really die. Although the MCU universe is different from Norse Mythology, Hela is the Goddess of Death and the ruler of Niflheim. As we know, Hela draws her power from the realm of Asgard itself, but since Asgard was destroyed, her powers would have been diminished. Many fans have believed that she is in fact Lady Death. The Russo Brothers have promised that Death won't appear in any of the MCU films and merging Hela with Lady Death in Avengers: Endgame will convolute the whole plot. However, Hela does have a lot of room to return in Avengers: Endgame. Around May 2017, filming for Avengers: Infinity War (which is most likely for Avengers: Endgame) occurred, and Chris Hemsworth, Tessa Thompson, Mark Ruffalo, Tom Hiddleston, and Cate Blanchett were the notable actors who were spotted in the area. At the cathedral, there were props, such as an Asgardian statue as well as a Celtic door, which were used in Thor's nightmare sequence in Avengers: Age of Ultron. In an interview with Cate Blanchett, the same Asgardian statue was seen in the surrounding area. Avengers: Endgame draws inspiration from Return of the King, and Thor takes on the role of Aragon, who recruits an undead army. So it's possible that Thor travels to Hel and bargains with Hela. Cate Blanchett has also expressed interest in reprising her role in Avengers: Endgame</p><p>
</p><p>
Nova Corps- Avengers: Infinity War did not include the scene of Thanos obtaining the Power Stone. Since Xandar was not in Avengers: Infinity War, the Nova Corps could possibly make an appearance in the last A4. The Avengers could obtain the Power Stone from Xandar in the past and a few corpsmen such as Irani Rael and Rhomman Dey could make a cameo.</p><p>
</p><p>
Collector- The Collector, who appeared in Avengers: Infinity War, was confronted by Thanos, who pillaged and destroyed his museum after he retrieved the Reality Stone. Benicio del Toro confirms that the Collector survived Thanos's assault on Knowhere. Since time travel is happening in A4, a few Avengers could travel to Knowhere to obtain the Reality Stone from the Collector, which was at the time in the state of the liquified Aether.</p><p>
</p><p>
Kraglin Obfonteri and other
Ravagers- Fans were assured by James Gunn, through a post on social media, that Kraglin has not been forgotten, and will make an appearance soon. Possibly, Tony Stark and Nebula are rescued by the the Ravagers.</p><p>
</p><p>
Odin- Since Odin met his end during Thor: Ragnarok, it is possible that he could appear to Thor in a vision, in which he advises him to travel to Hel to raise an army of undead soldiers from Hel. Since Frigga is reported to return, why shouldn't Odin?</p><p>
</p><p>
T'Chaka &
Erik Killmonger- Although very unlikely, it would be interesting and funny to see both these characters in the Ancestral Plane giving Shuri advice.</p><p>
</p><p>
Jasper Sitwell,
Phil Coulson,
Jack Rollins- Clark Gregg has not ruled out the possibility of a small cameo for Phil Coulson in Avengers: Endgame. Jack Rollins was credited for Avengers: Infinity War, but never appeared in the film. Jasper Sitwell's actor Maximillio Hernandez was spotted at an Avengers 4 charity event or something. Since set photos show the Avengers travelling back to the Battle of New York and given that Crossbones is returning in the film, along with other surprising characters such as Ancient One and Frigga, we might see a few S.H.I.E.L.D. agents such as Phil Coulson, Jack Rollins, or Jasper Sitwell interrogating a restrained Loki.</p><p>
</p><p>Barton Family- The released Avengers: Endgame trailer features Hawkeye slaughtering Japanese hostiles (presumably members of the Yakuza) for some unknown reason. Fans have speculated that he now assumes the persona of Ronin. It is possible that his whole family was snapped, motivating him to become Ronin. For those who remember that Clint Barton was on house arrest, well I don't think that matters when half of the universe was killed off. </p><p>
</p><p>
Chitauri &
Outriders- Not all the Chitauri and Outriders were wiped out, so it is likely that Thanos could command a horde of these creatures in the final Avengers movie.</p><p>
</p><p>
Black Order &
The Other- Since A4 deals with massive time travel, what's to stop the Black Order or The Other from returning in Avengers: Endgame. I mean if the Avengers are fighting off against Thanos in unison, one would think he would have formidable reinforcements, other than the Chitauri and the Leviathans.</p><p>
</p><p>Undead Asgardian Army- Since Avengers: Endgame draws inspiration from Lord of the Rings: Return of the King, Thor, Captain Marvel, Valkyrie, War Machine, and Rocket Raccoon could travel to Hel to obtain an undead Asgardian army with Hela's help. Perhaps, he could also meet his fallen friends, such as Heimdall, Volstagg, Sif, Fandral, or Hogun, although highly unlikely. </p><p>
</p><p>
Quicksilver- Ever since his death in Avengers: Age of Ultron, fans have speculated if Quicksilver will return in Avengers: Endgame. Actor Aaron Taylor Johnson was spotted in Atlanta around May 2017 during A4 filming. So does that mean he'll return. The actor gave up hopes for fans, stating that it was irrelevant. But he could be concealing the fact that he is actually in the film.</p><p>
</p><p>
Nick Fury &
Maria Hill- As both are credited to appear in Spider-Man: Far From Home, the odds are high that they will appear in Avengers: Endgame.</p><p>
</p><p>
Lady Death- Even though Avengers: Endgame will 99% not merge Hela and Lady Death, what if Lady Death actually appears in the film. Last I remember, her one and only mention was during the post credits scene of The Avengers. What if Death, or a more powerful mysterious villain is lurking in the shadows? </p>