Mainstream universe
(Capcom's primary storyline)

Greg Mueller was an Umbrella researcher who rebelled against the company.


Greg was assigned to the Umbrella R&D Center in Raccoon City.[1] After William Birkin assigned his T-virus Project to him, during his time there, he was involved in the events surrounding the Arklay hospital and the illegal human drugs trials being conducted there.[2]

Sometimes in 1996, one of his students, Yoko Suzuki, was involved in the T-Virus project by donating her cells. Greg operated on her to alter her memory.

At one point, he began researching into the experimental "Tyrant"-class B.O.W., which he attempted to develop on his own. The fruit of his work was "Thanatos", a seven-foot-tall killing machine. Unlike other Tyrants made that year, Thanatos was a very intelligent, strong, and agile creature.

However, when Umbrella began plans to mass-produce the Tyrant, Greg became furious, believing that this would take away from the individuality and uniqueness of his subject. Like many Umbrella researchers, Greg viewed his creations as pure works of art, not mass-production weapons as Umbrella intended, refusing to help them any further.

To further spite Umbrella, Greg helped Peter Jenkins, a Raccoon University professor, to create a cure for the t-Virus, Umbrella's most prized viral weapon.

Due to his rebellion, Greg was marked for assassination by Umbrella, who sent a U.B.C.S. team to assassinate him and retrieve a blood sample from Thanatos in the early hours of October 1, 1998. Anticipating this, Greg intended to have Thanatos eliminate his would-be assassins. Thanatos largely achieved this, quickly killing off a UBCS squad. However, a UBCS Monitor, Nikolai Zinoviev, ultimately managed to shoot Greg in the head with a silenced pistol from above the ceiling in the Second Hall, and a large amount of blood spilled from under his chin, death being instantaneous.


"Too much growth weakens an organization, which what should be important becomes overshadowed by greed. Mass production?! Ridiculous! [...] One masterpiece is enough!"
— Greg in the opening cutscene of Decisions, Decisions.

"My apologies for this place being so... hectic. I have been monitoring your progress from here. I am grateful for your assistance. Daylight is it. The only resource against the T-virus. I cannot give it over to Umbrella. They're the ones responsible from the catastrophe which has befallen the city. In retrospect, the entire "t" project was a total disaster. Brute force should not be the only criteria for a weapon. It must also be beautiful, unique, and God-like. You will also assist me. You're going to play with my ultimate creation."
— Greg talking to the survivors in the Second Hall.

"Yoko, it's been two years... oh, but you might not know that. After all, what happened was so terrible... I think you'd want to erase it from your memory."
— Greg talking to Yoko in the Second Hall.


Greg is unlocked after completing the scenario Decisions, Decisions on VERY HARD difficulty. His set costs 10.000 points. Alternatively, he is already unlocked in File #2 and can be purchased for a much cheaper price (1.000), and can be transferred to Outbreak via the Data Convert.

The following is a translated adaptation of information found in the BIOHAZARD OUTBREAK FILE 2 GRAND BIBLE.

Infection rate
1.21% per minute
Movement speed
Attack modifier
Starting condition
Starting items
Anti-Virus (L) (Outbreak)

Anti-virus X3 (File #2)

The following is a transcription of information found in the BIOHAZARD OUTBREAK FILE 2 GRAND BIBLE.

1.21% per minute
Anti-Virus (L) (Outbreak)

Anti-virus X3 (File #2)


  1. Resident Evil Outbreak File #2, special item: "Gold Glasses".
  2. Resident Evil Outbreak File #2, file: "Sealed Letter".

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