The Master Chief is he just a Warrior trained only for combat and to fight wars essentially a Machine or just like the rest of his fellow UNSC personnel...Human?. Due to the comments that was said about my first blog "Master Chief - Unmasked" alot of the users commented on how the fact they like the direction that 343i's was taking and  that the Master Chief face was shown and the way he is acting and thinking more like a human. Indeed 343i's is definately changing the way the Master Chief was than in the previously Halo Saga as to being more human than a trained killing Machine. In a way this Master Chief that we play in Halo 4 is much more different, first his much short dialouge and silence is changed as we see that he is more interactive wich is kind of different than his use to being the silent type, and also his feelings are more shown than supressed as mentioned in the books and the previous Halo Saga. Halo 4 has definately shown us a different side of the Master Chief how is last words were with Cortana and his feelings about them can be seen even under his helmet you can tell by his body language, and also at the end of Halo 4 his talk with Captain Laskey. The Master Chief originally conscripted by Dr. Catherine Halsey of the Office of Naval Intelligence (ONI) with 75 other six years olds of the first generation of Spartans (Spartan II's) were created to be invisible augmented Super Soldiers ready and trained for combat. In the epilouge for Halo 4 Dr. Halsey is interregated by some mysterious character as describing the original Spartan II's just trained War Machines meant only for war as if they have no feelings for their much large success in the field quoting "Do you think thee Spartans lack of basic humanity helped?.....Records show Spartans routinely exhibily showed midely sociopathic tendencies, difficultly with socialization. Basically the Spartan II's were not meant to live their lives and just serve the UNSC for a period of time they were meant to be Warroirs to be giving daunting missions that no normal soldier could accomplish and without fear of death. 

"Our duty as to protect humanity...whatever the cost" - Master Chief

"You say soldiers and humanity are two different things...soldiers aren't machines....they're just people. - Captain Laskey