The core teachings of the Ishgardian Church can be found encapsulated in a single book of scriptures, called the Enchiridion. Unlike other sects that worship the Twelve, the Halonic doctrines are very strict, and deliberately reject outsiders who do not conform.
Speaking out or disobeying the teachings of the Halonic church is a very serious crime, and violators of this are branded "heretics." Even consorting with other known heretics can be considered an offense worthy of punishment. The Tribunal exists to investigate accusations of heresy and dispense "justice" if necessary. Those accused of Heresy are allowed the right to Trial by Combat, or the right to have a champion fight in their name if they are unable to fight.