Jacob was a Fifth Column supporter and a secret worshiper of Xon. He was a technological genius and was respected by many. At the height of his career, he was head of the Institute of Science and decorated personally by the Leader as a "Hero of the State" and is considered by many, including Willie and Lydia as a father of Visitor technology. As his age advanced, his body began to tire and eventually went blind and realized that all of his discoveries, despite his original intentions, were made for destruction. This made him adopt a firm pacifistic nature and an abhorrent view on warfare, considering it a waste of life. However, he had to keep his views a secret, for fear of being accused of "putting individual conscious before duties of state". During the Second Invasion, Jacob's greatest creation; The Forcefield, an impenetrable energy barrier isolating a 50-square-mile (130 km2) area of a planet's surface, was employed by Nathan Bates to isolate Los Angeles and cut off the Resistance's weapon supplies. When Diana ordered Jacob to refine the code in the Master Computer to make the Forcefield work properly, he refused and expressed his belief that the entire Earth war effort a "waste of life". He states he wont be a tool for destruction. Diana threatens him with conversion, but he still doesn't talk. Diana begins the conversion process on him, making him give her the code. Before his conversion was completed, he was rescued from the Mothership by Mike Donovan and Ham Tyler, who needed his help in destroying the Forcefield. He escaped back to Earth and, linking up with Kyle Bates and Elizabeth Maxwell, the team reached the entrance to the Forcefield. Jacob then told Elizabeth she was the future and must survive, at any cost. He then used his soborium bracelet to overload the Forcefield's power grid, causing the Forcefield to self-destruct. Jacob vanished in a funnel of energy, presuming to have died.