Harry Osborn Is Really Sick

Largely unseen outside of photos and diary entries in the first game, Harry Osborn becomes a major cast member in Marvel’s Spider-Man 2. Having lost his mother to Oshtoran Syndrome at a young age, Harry eventually learns that he has inherited the rare disease, keeping it a secret from M.J. and Peter until he becomes too sick to hide it. During the events of the first game Peter and MJ are led to believe by Harry and his father Norman that Harry has gone to Europe to manage Oscorp’s international interests, but M.J. eventually discovers that this is a cover for the fact that Harry has had to undergo a years-long period of stasis as part of an experimental therapy to cure him.
A post-credits scene reveals that Norman’s desperate attempts to cure first his wife, and then his son of Oshtoran (of which Devil’s Breath was an early failed experiment in doing so) have led to him keeping Harry in secret within his own Manhattan penthouse, hooked up to a large regenerative vat full of green liquid and a strange, goopy black substance that begins bonding with the unconscious Harry. Best not worry about that one, it probably won’t come up at all in the new game.