As a lowly cleric, you have learned the power to dispel good. It was useful to get rid of all the naive little fools who helped forces of good, but as your own power grew, it is not enough. Fortunately, you discovered (or perhaps tortured out of someone, you are evil, after all) a powerful, unholy word, mere utterance of which will send all the servants of good forces packing. You must of course be evil to successfully use this spell.