Theory: Elle Fanning's character (Tomorrow) will either be the second playable protagonist, or a twist villain, or both.

I think that Tomorrow will be the second playable protagonist alongside Sam, and/or maybe even a twist villain. Spoilers for DS1 below.

Evidence for

  • Marketing for DS2 has been really cryptic and mysterious in regards to Tomorrow's character. Even though Elle Fanning has a starring role in the game, her character is only truly shown for the last 10 seconds in DS2's second trailer, and she doesn't even say a word. Kojima wants her role in the story to be a surprise.
  • Tomorrow is clearly not a normal human as evidenced by the TGA cutscene of her: she's confused by the human cycle of living, and the cycle of living is a big theme in DS1 which was used as a motive for destruction by the two "antagonists" Amelie and Higgs.
  • When she is shown in her normal form in the last 10 seconds of the second trailer, she's eavesdropping with an expression on her face that suggests she's up to no good. The way she walks away especially, it seems like her mind is made up on doing something.
  • The opening scene of the second trailer is an autopsy/operation on Tomorrow. She's covered in tar, but not only on the outside like the other humans, there's tar inside of her. Maybe she's a BT entity similar to Cliff Unger in DS1? Or perhaps she can manipulate BTs with DOOMs like Higgs/Amelie?
  • You can see she has faint strands going out of her, upwards. DS2 has been marketed with strands going upwards instead of downwards like the first game. This is probably a strong indication that Tomorrow will be important to the plot.
  • The only antagonist confirmed so far in DS2 is Higgs. The first game had both Higgs, the smaller villain, and Cliff Unger, the bigger, overarching villain, as threats. This leads me to think that DS2 has a second villain in store for us, someone bigger than Higgs.
  • Metal Gear Solid 2 has a twist - a character that people weren't familiar with from the first game was the protagonist for the second game. Maybe Kojima's going to do something similar again?
  • The first game explored Sam's character, relationships and origin in great detail. It wouldn't make sense to make another game that would just be about him again. Overall I think this game will focus on Sam and Tomorrow's relationship.

Evidence against

  • In the TGA cutscene, Tomorrow isn't really portrayed as a potential twist villain. She seems bumbling and innocently curious. However, it's clear that this scene takes place early in the game, and this may be a case of "innocent character slowly gets corrupted over time".
  • Photo mode. The fact that she's included in this suggests she won't be an antagonist.
  • Dollman. The inclusion of this character as a companion makes the possibility of dual protagonists a little lower, since we see Dollman being given to Sam only, and it wouldn't make sense for Sam and Tomorrow to swap hold of Dollman each time the protagonists switch.
  • Kojima stated that there will be a contrast between Sam's hardships on the outside during his journeys against the easy nature of the crew's lives. This suggests that perhaps Tomorrow won't leave the crew's ship, the Magellan, and will not go through any difficulties during the plot, emphasising that Sam is the special one in this story and that the plot will revolve around him again.

Evidence I'm unsure about

  • The possibility of Tomorrow being Lou grown up. If she really is Lou, then that would confirm her strong importance to the story. It would then make sense if she was a second protagonist. Her being a twist villain would make sense and not make sense at the same time, so I don't really know about that one.
  • If she isn't Lou, then the probability of her being important to the plot is quite low. If this is the case then she'll probably be just a side character's that's superficial in the game's overarching story, similar to Heartman or Mama from DS1.