Champ is an excellent fellow -- a large, ferocious, baying hound who hurtles down upon the crowd of young people trudging up the drive towards Stallery Manor in search of a good job as a lackey of some kind. He is quite scary to most of the youngsters, but when Christopher marches towards him saying damping things in a very firm tone of voice, he turns into a groveling, tail-wagging puppy of a ferocious hound after all.
And later when Christopher and Conrad run across him lost in the shifting possibility landscapes of Stallery, he is tremendously grateful and anxious to find his supper, which actually helps the two boys get back into the manor house without too much fuss.
A big fan of Christopher, Champ is basically a pussycat.