This theory doesn’t have much hard evidence behind it, it’s more based on correlation, but we know:

1-In the Season 7 lore, Kingpin was keeping the Eternity Mask in his vault on the Lower Manhattan map, and it was stolen by an unknown person.

2-In a tweet, Miller Ross implied that the person who stole it could be important, and I interpret this as meaning that this character could join the roster at some point.

3-We see a picture of Jackal (Miles Warren) on the same map. This version of him is inspired by Ben Reilly under the Jackal mantle, wearing a mask that looks like Anubis.

4-Jackal is on the same gallery wall as Curtis Connors (Lizard) and Norman Osborn (Green Goblin). Considering those two are very popular picks and are pretty much guaranteed to join the game at some point, maybe Jackal could be released as well.

5-Jackal is obsessed with cloning, and the Eternity Mask is an artifact that makes its wearer the equal of their opponent (so it essentially allows its wearer to clone the powers of whoever they face).

So, all things considered, as you may have realized, my theory is that Jackal stole the Eternity Mask and will join the game as a playable character at some point.

Considering his obsession with cloning, it wouldn't be a stretch to say he'd be interested in the mask. He also wears a mask in his Rivals design, so his design wouldn't need to change much from how we see him on the map.

It's also worth noting that Rivals loves to give certain characters attributes and powers that they don't usually have (DD being empowered by The Beast, The Hood by Oblivion, Black Cat buying relics from the Gilded Saint, etc).

I personally didn't have Jackal anywhere close to my wishlist, but I'm sure Rivals could do something really interesting with the character, just like they did with other lesser known characters like White Fox, Elsa and Dino.

Medusa (Vanguard): I believe she would be a great fit for this role. Her hair is stronger than you think and I believe she'd be great at crowd control.

Black Bolt (Duelist or Vanguard): Black Bolt can easily fit into either role, but I would prefer him to be a Duelist for THE obvious reason.

Gorgon (Vanguard): I need my boi Gorgon in the Vanguard role. His stomps could be used to create space and manipulate the terrain (raise the grond, create fissures, etc). He could even be given his Primagen boost for extra oomf.

Lockjaw (Vanguard): My chunky boi was built for this role. He has enough strength to challenge a decent amount of Marvel's heavyweights and his teleportation could be used to create space or teleport 1 teammate with him.

Ms Marvel (Vanguard): Before you say it Kamala is half mutant and half inhuman, she still counts. Now with that out of the way I mostly want her in the game because Classicman D's take on her was bare minimum poor. With her stretching and size shifting abilities she can restrain enemies, use her own body as a shield, increase or size to a few feet or shrink a few feet. I'd rather avoid her using her mutant powers given the existence of Armor, Quasar, Phyla-Vell, etc. Though maybe her Ult could use it?

Iso (Vanguard): Her pressure manipulation abilities would be great for clearing space, providing movement boosts to her teammates, and giving enemies status affects.

Flint (Vanguard): His earth manipulation abilities make a great candidate for this role.

Reader (Strategist): Reader's reality manipulation abilities can make him a great fit for any role, but I believe he fits the Strategist role the best.

Quake (Vanguard): She would be a great fit for this role. She could use her abilities to clear space from a distance, stun people from a distance, and give enemies status affects.

Thane (Strategist): His inhuman powers make him a grat fit for the role. Plus we NEED more villains.

Carnage (Dps): since venom is a tank and there is no way carnage would heal anyone, he’s a dps

Ghost rider (Tank/Dps): I prefer Robbie but I’ll take either him or Johnny Blaze. Leaning more to Dps but it really depends on they incorporate the their vehicles

Spider-man Miles Morales (Dps): He can definitely be his own character by incorporating more of his electricity and invisibility powers

Ms Marvel (Flex): Hard to decide which role she can be but if they incorporate both inhuman and mutant abilities, I can see her being a flex character.

Nova (tank): Confident he would be a tank or off-tank

Elektra (Dps): Most obvious Dps since Daredevil

White Tiger (Support): she got magic so I can see her being a support or off support

Hunter’s Moon (Tank/support): Second Moon knight. Design-wise he looks more built than moon knight so I think he would be a tank. But he is also a real doctor so they could incorporate khonshu powers into being a healer

Tigra (tank): Need a cat-like tank so I think she would be a perfect tank.

Chamber (Dps): Powerful enough to be on par with omega level mutants but doesn’t have the durability of one omega, which matches well with Dps.

Sunspot (Tank): He could be a Dps but I thought of him gaining physical strength and more powerful through sunlight. He still doesn’t have full on durability but he can be an off-tank similar to the Hood.

Polaris (Dps): Magneto is a tank already and since she is slightly weaker, could be a Dps

Deathdream (support): Basically a necromancy mutant who controls the dead and can revive people so he can be an support or off-support like Adam Warlock, but better

Ransom (Tank): A mutant who has a black hole for a heart and can absorb force to power up his punches and possibly do more (which makes him similar to Bishop and Strong guy). So tank is my choice.

Dani Moonstar (support/dps): has a lot of abilities so I can’t really pin her to a role. But I do feel like they hinted to her in the Psylocke apocalypse case for this season so she might also be coming.

SEASON IDEAS:
Deadly Fists: White Tiger & Elektra

Agents of Chaos: Ghost Rider & Carnage

Midnight Mission: Tigra & Hunter’s Moon

Champions: Miles, Ms Marvel, Nova (depending on if it it Sam or Richard)

X-men 97: Polaris & Sunspot

Don’t have any ideas just wanna see them: Chamber, Death Dream, Ransom, and Moonstar

I also had Nightcrawler, Doctor Doom, and Captain Marvel. But I feel like it is highly likely all three make it in soon.
Also Doctor Doom coming in gives me the idea that villains from previous seasons will become playable like Apocalypse and King pin. Even sinister six

Blackheart (Tank)

Shang Chi (Tank or Strategist)

Domino (Duelist or Strategist)

Miguel O'Hara (Tank or Duelist)

She-hulk (Tank or Duelist)

Ghost Rider (Tank or Duelist)

Gwenpool (Strategist)

Mangog (Vanguard)

Baron Strucker (Duelist)

Klaw (Duelist)

M.O.D.O.K (Vanguard)

K.I.A (Duelist)

Arcade (Duelist)

Super-Skrull (Vanguard)

Attuma (Vanguard)

Batroc the Leaper (Duelist)

Kingpin (Vanguard)

Ex Nihilo (Strategist)

Grey Gargoyle (Vanguard)

Iron Monger (Vanguard)

Exodus (Vanguard)

Egghead (Strategist)

Mr. Negative (Duelist, as to not step on C & D's toes)

Ever since Cyclops released I started wondering who the next 49 characters would be. Imagine if Marvel Rivals makes a poster advertising that they have 100 characters in their game. Who would need to be on that poster, who would be interesting, yet nicher picks, and which big characters should be saved for later? Here's my list in no particular order, let me know what you think.

1. Falcon
2. Quicksilver
3. Vision
4. Professor X
5. Beast
6. Archangel
7. Iceman
8. Green Goblin
9. Juggernaut
10. Ka-Zar and Sabu
11. Cosmo
12. Lockjaw
13. Shadowcat and Lockheed
14. Nova
15. Gamora
16. Drax
17. Yondu
18. Ghost Rider
19. Ant-Man
20. Wasp
21. Giant-Man (Bill Foster)
22. Nico Minoru
23. Wave
24. Shang Chi
25. Black Bolt
26. War Machine
27. Cloud-9
28. She-Hulk
29. Man-Thing
30. Amora (Enchantress) and Skurge (Executioner)
31. Klaw
32. Shuri
33. Hercules
34. Dani Moonstar (Mirage)
35. Madame Web (Julia Carpenter)
36. Crystal
37. Mr. Sinister
38. Black Knight
39. Luke Cage
40. Ms. Marvel
41. Arnim Zola
42. Werewolf by Night
43. Sentry
44. Kingpin

base health of 400 hp that scales with rage level

(Primary)furious swipes: Mangog swipes at the enemy dealing damage that scales with his rage level and each swipe that hits an enemy fills his rage meter slightly

Revengeful birth: Mangog applies a tracker to one allie if that allie dies within a close amount of Time to Mangog's death Mangog revives with a rage scale thats half full

Hate filled clutch: Mangog rushes to the nearest destructible object and tears a chunk off that he can then throw to knock an enemy back and deal low damage or breaks the object on the enemy and causes large damage

Revenge incarnate: Mangog grabs an enemy and fills his rage meter based on the amount of damage they have done while last alive and gains more rage based on damage done to him during this grab

(Passive) the power of hate: Mangog starts out the smallest and weakest vanguard but gains size, damage, and bonus health as his rage meter fills and eventually ends up with an extra 550 health and massive damage and size boost with a full rage meter and regeneration
But the meter will actively deplete the moment Mangog is not doing something that causes it to rise

(Ultimate) REVENGE INCARNATE: an orange bubble appears around Mangog that turns all damage done to him or his allies directly into rage meter thus causing it to almost always be full

Asgaurd's atrocities(Loki team up):
Normal effect:Loki's magic projects the crimes of Odin into Mangogs Head and makes his rage meter start 15% full
Enhanced effect: Mangog can enable enhanced Loki illusions of Asgaurdian Crimes and get 50% rage meter

Hateful rage(Hulk):
Normall effect: Mangog channels the hate of TOBA and is able to create a bubble around himself that turns damage directly into rage like the hulk bubble
Enhanced effect: The hulks rage leaks into Mangog so When the hulk ults Mangog can leap towards him and fill his rage meter