A perversion of pleasure

The theologians tell us that cruelty comes from the devil, and this may be the ultimate cause, for it is most certainly evil in intent. But in its immediate cause I do believe that true cruelty comes from a perversion of pleasure, for the cruel man enjoys the torment he inflicts on others and, like an experienced musician with his viol or virginal, can play upon his instrument and make all manner of harmony, exciting torment and humiliation, distress and empty anger, shame, regret and fear at will. Some can produce all of these, together and singly, with the most delicate touches, sometimes playing more loudly on his subject until the motion excited in the mind is all but unbearable, then more softly so that the misery is summoned gently and with seductive delight. Such a man as Grove was an artist in his cruelty, for he played for the pleasure of his creation, and the delight of his skill.

Iain Pears
An Instance of the Fingerpost