This should be about Arnold as a past special opps use to be the assassin for the Government and that Sarah  
is your daughter so now Skynet want to get to Arnold for codes that he has and information that candestroy skynet its a fail safety mechanism and after the war The Survivors are looking for him as well as skynet a continuation from Terminator 3 or it can be a new evolution of the first T-100 but have Arnold DNA is needed and the codes so they can not kill him but capture then extract and finally kill off the character Saving his family.  the idea of a terminator came to being (The way that the Terminator kills and everything about the Terminator is based entirely on Arnolds method as a special opps his focus his emotionless and relentless drive to getting the job done