Jacob Wesker (née Boyd), also known as Subject-1 to Alex Wesker, was the first of ten test subjects that participated in the Wesker Project - Mk. II. He was voluntarily donated to the project by his father and Neo-Umbrella employee Norman Boyd. He was the only member of the second generation of Wesker children that was not infected with the p-C Virus, as he was injected with an isolated strain of what was dubbed the "H-Virus". While his first years were highly successful, he started to develop Peripheral Vascular Disease, and eventually died due to an Aortic Aneurysm.
Jacob's death was considered the catalyst for the creation of the p-C Virus, and also for the death of his parents, which described as "a punishment for treason", although it is speculated that he had them killed due to the failure of Subject-1.