From chapter 13 of white fang

Grey Beaver is the master that teaches White Fang the lessons of the gods. He is a neutral master, neither as cruel as Beauty Smith, nor as kind as Weedon Scott. Grey Beaver was a noble "savage" who Buck only saw as a man-God but had no affinity to.

There was something in the fibre of White Fang's being that made his lordship a thing to be desired, else he would not have come back from the Wild when he did to tender his allegiance. There were deeps in his nature which had never been sounded. A kind word, a caressing touch of the hand, on the part of Grey Beaver, might have sounded these deeps; but Grey Beaver did not caress, nor speak kind words. It was not his way. His primacy was savage, and savagely he ruled, administering justice with a club, punishing transgression with the pain of a blow, and rewarding merit, not by kindness, but by withholding a blow. ch 13