The True were the gods of the Ascendants. The Ascendants do not know the True's real name nor where they are and spend their entire lives searching out the Fortress, the home of the true in the hopes of receiving judgement from their gods.
The Ascendants spend their lives searching for the True, but also purging the galaxy of others who worship them, considering them unworthy of the right. One such race targeted by the Ascendants were the Eav'oq who worshipped the Siblings, the same beings the Bajorans know as the Prophets. (DS9 novels: Rising Son, Sacraments of Fire)