Jake Muller appears as one of three main protagonists in Resident Evil 6.
He is the illegitimate son of the Albert Wesker; it is believed that Wesker was not aware of his son's existence, as Jake's mother left shortly after being impregnated by him. Jake, later works as a freelance mercenary in order to support his mother, whom dies of an unknown chronic disease shortly after Jake receives money for her treatment. Jake was caught up in an act of bioterrorism while operating in anti-government operations in the fictional Eastern European republic of Edonia.
His mercenary comrades are infected with the C-virus, but Jake's specialized blood resists the infection. Soon after, he meets US government agent Sherry Birkin – whose father, Dr. William Birkin, was coincidentally Albert's research partner. Sherry and Jake take part in the subsequent battle between the Bioterrorism Security Assessment Alliance and the mutated mercenaries. With his blood resistant to the downside-effects of mutagenic viruses like his father, Jake also inherited several of his father's signature abilities such as increased strength, speed, healing, and advanced combat skills. He demands a large sum of money from the BSAA, in order to sample a pint of his blood to be synthesize for vaccination to combat the C-virus. He and Sherry are captured by Carla Radames, a doppelgänger of Ada Wong, and held captive in Lanshiang, China.
They escape during the C-virus outbreak in the city six months later. Over the course of the story of RE6, Jake comes to terms with both the knowledge of his father's actions and of his death at the hands of Chris Redfield three years earlier. After the ordeal, Jake starts a new life fighting BOWs in an underdeveloped country with his real identity covered up by the BSAA.