Cleric

Clerics bear the sacred responsibility of carrying the divine message of their patron deity to his mortal followers. Of course, in Ravenloft, this message is likely to be the Lawgiver’s ceaseless demands of obedience or of Zhakata’s ravenous cruelty as it is to be the words of hope offered by deities such as Ezra or the Morninglord. Clerics in Ravenloft may be the shepherds of their congregations, adventuring to remove the faithful from danger, or they may be itinerant priests, preaching the word of their deity in the earnest hope of converting new followers to their faith. Then again, they might be depraved cultists, secretly carrying out the obscene mandates of their foul patron.

Altered Class Features

Spells: Some spells function differently in Ravenloft.
Spontaneous Casting: If they want, evil clerics of non-evil deities can opt to channel spell energy into either inflict or cure spells in the same manner neutral clerics of neutral deities. This choice usually determines whether the cleric channels positive or negative energy, but the Dark Powers reward those who choose evil over good in their descent. Therefore, unless the specific deity commands otherwise, such clerics may choose to channel positive energy or negative energy with respect to the undead only. Naturally, healing the undead calls for a powers check (with the percentage based on how detrimental such a choice is to either the cleric, his companions or bystanders).
Channel Energy: The connection undead have to the Negative Energy Plane is strengthened in Ravenloft. All undead add +1 to their Channel Resistance. This modifier stacks with those imposed by a sinkhole of evil. All undead darklords automatically add a bonus to their Channel Resistance equal to +1 or their Wisdom modifier (if positive), whichever is greater.
Weaknesses: Good and neutral clerics who commit any questionable acts that call for a powers check must do so at twice the normal chance for failure. The Dark Powers offer seduction to all folk, but judge those whose power stems from the deiries most harshly.

Cleric

The Ravenloft Files: Dead of the Night arkhemedes