Changes in Barovia

Introduction

The world of Barovia has been secluded from the rest of the universe and therefore has some changes compared to the normal world.

Religion

Barovia has been cut off from the other gods for generations. When Strahd came to Barovia he brought one religion with him; that of the Morninglord. As years continued evil had found itself into the world of Barovia, corrupting it with the believes of the Mother of Night.
If you plan on playing a class with religious ties, be aware that your connection will be tempered with or be completely non-existent. This doesn't mean that you can't play that class, but this does have to be discussed with the DM.

Magic

Similarly to religion, magic that pull their powers from a god outside Barovia or from a source of power where they must be on the same plane will have trouble adjusting to Barovia. Strahd can sense when someone in his domain is casting such a spell and can choose to make himself the spell’s recipient, so that he becomes the one who is contacted.

Altered spells

The land of Barovia resides in its own demiplane, isolated from all other planes, including the Material Plane. No spell—not even wish—allows one to escape from Strahd’s domain. Astral projection, teleport, plane shift, and similar spells cast for the purpose of leaving Barovia simply fail, as do effects that banish a creature to another plane of existence. These restrictions apply to magic items and artifacts that have properties that transport or banish creatures to other planes. Magic that allows transit to the Border Ethereal, such as the etherealness spell and the Etherealness feature of incorporeal undead, is the exception to this rule. A creature that enters the Border Ethereal from Strahd’s domain is pulled back into Barovia upon leaving that plane.
For the purpose of spells whose effects change across or are blocked by planar boundaries (such as sending), Strahd’s domain is considered its own plane. Magic that summons creatures or objects from other planes functions normally in Barovia, as does magic that involves an extradimensional space. Any spells cast within such an extradimensional space (such as that created by Mordenkainen’s magnificent mansion) are subject to the same restrictions as magic cast in Barovia.

Alarm: Instead of hearing a mental ping when the alarm is triggered, the caster hears a scream.
Bigby’s hand: The conjured hand is skeletal.
Find familiar: The familiar is undead—not a celestial, fey, or fiend—and is immune to features that turn undead.
Find steed: The summoned steed is undead—not a celestial, fey, or fiend—and is immune to features that turn undead.
Find the path: A child’s spirit appears and guides the caster to the desired location. The spirit can’t be harmed and doesn’t speak.
Fog cloud: Misty, harmless claws form in the fog.
Gust of wind: A ghastly moan accompanies the summoned wind.
Mage hand: The summoned hand is skeletal.
Maze: The surfaces of the demiplane’s maze are made of mortared skulls and bones.
Phantom steed: The steed resembles a skeletal horse.
Rary’s telepathic bond: Characters linked together by the spell can’t shake the feeling that something vile is telepathically eavesdropping on them.
Revivify: A creature restored to life by a revivify spell screams upon regaining consciousness, as though waking from some horrible nightmare.
Spirit guardians: The spirits appear as ghostly, skeletal warriors.
Wall of stone: A wall created by the spell has ghastly faces sculpted into it, as though tortured spirits were somehow trapped within the stone.