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Devil's Breath from MSM screen

The Devil's Breath, as it appears in the mission The One That Got Away

GR-27, nicknamed "Devil's Breath", is an imperfect medical treatment serum in Marvel's Spider-Man. It was designed by Oscorp, and later misused by Doctor Octopus as a bioweapon.

The serum appears as a red substance, and functions by combining CRISPR genome editing with AI-controlled gRNA to modify genetic mutations and errors in humans.[a] Should it ever reach completion, Devil's Breath could serve as a potential cure for genetic disorders such as cystic fibrosis and Huntington's chorea.

In its state during the events of Marvel's Spider-Man, Devil's Breath is more of a weaponizable disease than a cure. The treatment's delivery mechanism incorrectly attacks the patient's immune system, triggering rapid immunodeficiency and eventually death if left untreated. Additionally, the viral nature of Devil's Breath makes it highly contagious, giving it the potential to be the cause of a global pandemic. Devil's Breath appears to enter the body through the respiratory system.


Early historyEdit

As early as the 1980s, Oscorp co-founder Norman Osborn ordered the development of GR-27. Initial tests on a lab rat showed that while the treatment was effective, it would tear the body apart before it could heal it. Additionally, it proved highly contagious: while only one rat was given the treatment, it quickly spread to the other rats in containment, killing all of them within a week, earning it the nickname "Devil's Breath" from the lab technicians.

In 1986, Martin Li was given Devil's Breath as an experimental treatment by Osborn. Otto Octavius, Oscorp's other founder, was unaware of this until after Li was already injected. The treatment ended in tragedy: the Devil's Breath somehow granted Li superhuman powers, creating an explosion that killed his parents and sparked his grudge against Osborn. This incident caused a lawsuit, and Octavius left Oscorp in exchange for a settlement, ending his friendship with Osborn in the process. He would go on to found his own company, Octavius Industries. However, he was unable to reach the same level of success that he had at Oscorp, and was forced to rely on grants for employment.

Desperate to cure his wife's (and later his son's) Oshtoran Syndrome, Osborn insisted on continuing the project despite the obvious risks and legal violations. However, knowing that leaking the project's existence would be catastrophic to Oscorp and himself, Osborn ordered the utmost secrecy regarding the project. To mitigate the risk of exposure, Osborn trusted Dr. Morgan Michaels, the project lead, with the only sample of the unfinished treatment, with orders to keep it on his person at all times.

At an unknown point, likely in the 2000s, Osborn paid Wilson Fisk to build a facility for the production of Devil's Breath in Manhattan. It is likely that Fisk discovered the nature of Devil's Breath, as he referred to it as "Pandora's box", and kept a file on his findings for potential blackmail.

Marvel's Spider-ManEdit

Following the incarceration of Fisk, Li begins his crusade against Osborn, which includes finding and releasing Devil's Breath into Manhattan. He fails to do so, however, after Spider-Man and Mary Jane Watson stop his plans to release his first dose in Grand Central Station.

Upon becoming the vengeful Doctor Octopus, Octavius uses Mister Negative's scheme as inspiration for his own: to ruin Osborn, he releases Devil's Breath into Times Square. With the help of the Sinister Six, he intends to target Oscorp sites in order to push them to the limit, leaving them unable to handle the plague and therefore ruining Osborn and his reputation as the New York mayor. Knowing that Oscorp is developing an antiserum, he orders Mister Negative to secure it, keeping them from releasing it to the public – Octavius intends to distribute the antiserum himself once he has ruined Osborn.

Within 24 hours, Manhattan is in a state of disarray, and Oscorp's role in the creation of Devil's Breath is revealed to the public.

GR-27 antiserum from MSM screen

The GR-27 antiserum

Doctor Octopus finally captures Osborn, intent on forcing him to confess to his "crimes". When he refuses, he is thrown from the top of Oscorp Tower, but is rescued by Spider-Man, who defeats Doctor Octopus and recovers the antiserum. Octavius is apprehended and sent to prison.

Spider-Man brings the antiserum to Dr. Michaels, who is able to study it and mass produce a cure, though it is too late to save May Parker, who dies sometime before the replication process. Afterwards, there is a monument in Times Square dedicated to "those lost in the Devil's Breath crisis", implying that May was not the only casualty.

The disaster causes Osborn to resign from his position as mayor in disgrace.


  1. While Devil's Breath has been in development since no later than 1986, CRISPR was not discovered until 1987. It is unclear whether this was an error on the game's part, or whether earlier forms of Devil's Breath were of a different nature.
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