The ultimate evil, as opposed to the ultimate badness is to deny higher humanitys potential to individually realize its aims in a state of freedom. Any attempt to create a philosophy that is eternal, and transcends time and space, and must hem in human freedom is a lie and a product of a particular individuals psyche, rather than an external reality.
Faith and feeling, even intellectual knowledge, is a product of a would-be masters physical and mental state of being, and nothing else. Thus, a person with a slave mentality will by definition produce an enslaving system of morality, which Nietzsche believes is characteristic of Christianity, which champions the weak above the strong. The more slave-like the mentality, the more the individual will fear the strong, and use morality as a tool against the strong people whom he fears.
It might seem that Nietzsches vision of morality, because it denies objective truth, encourages the individual that lacks the slave mentality to simply do whatever he wants. This would be a fundamental misinterpretation of Nietzsches philosophy, since to accept a prefabricated notion of freedom would not be part of the austere aesthetic of the philosopher, who demands discipline on the part of the master to truly realize his or her state of perfection.
A true master who sees the good within himself desires a perfection of body, mind, and spirit. Only a slave would enslave himself to the passions and pleasures he or she is told to enjoy, like the bread and circuses of the ancient Romans or the advertisements of today that suggest buying a certain kind of product will produce happiness. The master does not feel guilty for his superiority, or curtail his natural talents to be good but he also has the ability and the drive to stretch his mind and talents beyond the constraints of culture. Thus, for Nietzsche, while bad might be a synonym for being mean or not nice, in a conventional schema, true evil is conformity. Goodness is nonconformity, not compassion not empathy — goodness is being true to ones masterful self..