Like a number of other fighting genre video games that include a Story Mode of any kind, there are a number of characters found within the game that player can never access or battle with. In Marvel vs. Capcom: Infinite, the same exact thing can be said. There are exactly thirteen Non-Playable Characters found within Infinite, almost all of which will be battled with at one time or another in the game's Story Mode. Most of these characters play such a minor role that it wouldn't be expected for them to be played with outside of this Game Mode; however, it might come as a surprise that the major characters of Death, Ultron Sigma and Ultra Omega also can't personally be played with.
Non-Playable Marvel Characters (7 Characters):
Death, Green Goblin, Groot, M.O.D.O.K., Giant Symbiote, Ultron Drone, Xgardian
Non-Playable Capcom Characters (4 Characters):
B.O.W., Dah'ren Mohran, Doctor Light, Grandmaster Meio
Non-Playable Unique Characters (2 Characters):
Ultron Sigma, Ultron Omega