The gunslinger. Flashbacks

One of the reoccurring uses of style King uses is flashbacks. We are constantly getting a background to the gunslinger, and learn that he's had a pretty terrible childhood. We also get a little bit of unexpected sci-fi thrown in. It turns out, that he is from a different sort of 'dimension' or time period and through the man-in-black has the ability to jump around from time to time.
Here is one of the quotes about his childhood. Probably one of the most important;

"Cort walked over to where the boys stood, casually, and swung his huge and twisted fist at Cuthbert's ear. The boy fell over without a sound, although his lips writhed back from his gums. A trickle of blood flowed slowly from his ear and onto the rich green grass. 'You were slow, maggot,' he said" (King 103)
It shows how in the gunslinger's world, those who were to follow the occupation of gunslinger had to face manhood at an early age. They were repeatedly beaten until they submitted. This probably the reason why the gunslinger is so heartless.