The Mortanius Court is associated with water and death.
Its function is to administrate the afterlife and the passage of souls between existences. The Mortanius Court upholds the Laws of the Death (or the Codex Mortanius) in a rigid manner. The Mortanius gods are responsible for maintaining the True Hells. The Death Gods uphold the Codex Mortanius, the graven stone plates that clearly articulate the laws of Chaldis. In essence, a mortal is to live their allotted span of days and then, upon death, they are to descend to the True Hells and suffer through the Seven Torments, so that they may be purged before their next incarnation. The Death Gods have a black and white view of existence. Those who obey the laws are protected and rewarded.
Those who disobey the laws are punished harshly. The Death Gods expect mortals sworn to their court to banish undead to the True Hells and thwart those who scheme for immortality, godhood and to escape the Wheel of Ages. In particular, the Death Gods expect their followers to thwart the schemes of the Disayr Court, especially those that focus on luring mortal souls into the Chaos Hells and away from the Wheel of Ages.
During the War in Heaven, the King of the Mortanius Court, Dagobh, was defeated and bound into the walls of the Chaos Hells. During the titanic battle, many souls escaped before the True Hells court be sealed once more. These souls manifested upon Chaldis in terrible monstrous forms, twisted by their torments, still clinging to memories of their previous existence. These monstrous “fallen” are still hunted down in the modern era by servants of the Mortanius Court.