John Connor was the leader of the organized human resistance and Tech-Com against the machines of Skynet in the year 2029. Imprisoned in a Los Angeles Skynet Work Camp, Connor began to train his fellow survivors to fight and slowly began to take control of the Camps, recruiting more men from each area they liberated. While they were vastly outgunned by their Terminator guards, the humans were pushed to the brink of desperation and had numbers on their sides, allowing them to gain the upper hand before going on to form the Resistance. This Resistance was able to gain the upper-hand against Skynet under John's leadership in the War Against The Machines in 2029, forcing the machine oppressors to turn to a new plan; they sent multiple T-800 and T-1000 series Terminators back in time to assassinate John Connor long before he could be a threat- when he was still a defenseless child. In response, Connor sent his ally Kyle Reese into the past, as well as a reprogramed T-800 of his own, to protect his child self and his mother, Sarah Connor.
The Child John Connor quickly became enamored with his T-800 protector, and attempted to teach it human emotion and befriend the machine. In the end, the T-800 sacrificed itself to save John and Sarah in a battle with the T-1000. After that, John began to live off the grid, though at one point he attempted to return to schooling under the protection of a Terminator named Cameron. Due to the future John and Skynet's interference with the timeline, multiple alternate timelines were created, diverging at different points leading to multiple universes of John Connor- some of them dying before they could lead the Resistance, some living in a timeline where Skynet never existed in the first place, and everything in-between.
Battle vs. Isaac Clarke (by Tomahawk23)
No battle written
WINNER: JOHN CONNOR
Isaac was far more mentally unstable, which drastically increased his chances of making a costly mistake. Additionally, Connor had more skill, and had fought against far stronger opponents than the Necromorphs. That along with having fought opponets with superior military technology, won Connor the day.