A disclaimer: This is a fantasy game. The portrayal of deities in this setting does not reflect the beliefs of anyone in the real world (so far as this writer knows, anyway), nor is any of this meant to be a "statement" on real world beliefs. The various clashes between the religions of the Warhammer World simply provide stock for plot possibilities.

HEROES AND RELIGION
Most of the time, the religion of any Hero is not going to come greatly into play. After all, this is a game about going into musty dungeons, beating monsters senseless, and taking their treasure, all in the name of saving the world. We aren't overly concerned with lofty moral messages in all of this. Advanced HeroQuest is something of a "(root) beer and pretzels" game. However, the Warhammer World has been richly defined, and one of the defining features of the setting is that there are many competing religious beliefs, and the Heroes might well be followers of one sect or another, united only by their common goal to fight the forces of Chaos.

It is not important for a Hero to proclaim what deity he intends to follow. Most heroes give whatever respect is due to the local deity, whatever he or she may be. Of course, if the Hero is a Warrior-Priest or a Light Wizard, then personal religion is determined by profession; otherwise, it's just a matter of choice and role-playing. Unless a player decides to choose a faith for his Hero, it's usually not cause for concern in the grand scheme of things.

However, some of the "magic items" introduced in some of my adventures are of a "holy" nature, and it matters who wields them. For instance, a "Hammer of Sigmar" is just fine if you worship Sigmar -- but not if you happen to be aligned with Ulric. In some cases, the rules for a particular item may dictate that it conveys special properties (bonus to damage, limited use of a Blessing, etc.) only if the user follows the deity it is consecrated to.

CHOOSING A RELIGION
A player may proclaim a faith for his Hero upon character creation. He may also experience a change of heart at some point during the adventure. If a Hero might happen to find a Breastplate of Ulric and subsequently decides to convert to the worship of Ulric just so that he can use the magic item, that's perfectly allowable in most cases. This is, after all, a pagan world, and quite a few of these deities are fairly fickle themselves.

Some common sense is suggested, however. A Hero carrying a Hammer of Sigmar and a Sword of Taal can't proclaim a sudden conversion between every battle, when he decides to switch weapons. In that case, both Sigmar and Taal are going to be mighty fed up with him; as GM, at the next trip to a settlement, have a prophet visit him and kindly suggest he donate the holy item to a nearby temple. If he refuses, then an "accident" (mauling by wild animals, struck by lightning) befalls him, the Hero is dead, and the item can go to a more worthy wielder. One does not trifle with the gods.

DIVINE INTERVENTION
It is not unlikely that a desperate Hero may call upon his deity for intervention in times of need. However, divine intervention is and should be rare.

The deities of the Warhammer World have very complex and unwritten rules for when and how they directly intervene in the affairs of mortals. (In other words, the player doesn't get any freebies for hamming up being "pious" in his faith. Hopefully, any interesting twists in the plot brought about by authentic roleplaying should be reward enough. Begging and pleading won't give the player of a Warrior or Wizard the same benefits he would have gotten if he'd chosen to play a Warrior-Priest.)

MAJOR RELIGIONS OF THE OLD WORLD
For a more thorough overview of the religions present in the Warhammer World, it is recommended that you look into the rich material provided for Warhammer Fantasy Role-Play. This is only a very crude summary of some of the major religions that Heroes are likely to observe.

SIGMAR
The state religion of the Empire is that of Sigmar, so it is a dominant religion amongst Humans, and also by Dwarves and Halfings within the Empire. Sigmar was historically the first Emperor and a great hero, who united the human tribes under a common banner to fight off the Goblinoid armies, did many other great deeds, then vanished mysteriously. His adherents believe that he ascended to godhood, and they show their faith with the Sign of the Hammer made across their chests in solemn remembrance. Symbols holy to Sigmar are the Hammer and the Red Gryphon; he is often symbolically depicted as a rampant gryphon clutching a warhammer. Warrior-Priests are followers of Sigmar.

ULRIC
Once a major religion in the Old World, the worship of Ulric is now secondary to Sigmar, and largely confined to the regions about Middenheim in the Empire. In the frozen lands of Kislev (allied to the Empire), however, the worship of Ulric is the state religion, and he is also dominant (as "Olric") in Norsca.

Ulric is a harsh warrior god, and also a god of winter and of wolves. His symbol is the White Wolf, often shown clutching a hammer, and his largest temple in Middenheim has a pack of white wolves allowed to roam freely within its walled groves. The especially devout followers of Ulric are sometimes said to be able to call packs of wolves to their aid in battle, but never to fight for the priest, but rather beside him. Ulric is a harsh god who despises weakness and trickery, and is especially unforgiving of it in his own followers. He favors directness in conflict over stealth or misdirection, and the ability to go berserk when in battle is seen as a special blessing of his followers. He has little patience for codes of chivalry that overly restrict a warrior's options. "Modern" weapons, such as black powder weapons, artillery and crossbows, are shunned. Ulric's following is exclusively human; the Elder Races are seen as weak and worthless.

Knights of the White Wolf, Ice Wizards and most Norscan Berserkers are followers of Ulric.

HYSH
The Serpent of Life, Hysh, is the representation of the North Wind, the Force of Light, the source of power behind the College of Light, and White Magic. Of all the Colleges, the Light Wizards are more like followers of a religion than detached practitioners of magic, and this is reflected in the fact that they are generally referred to as priests or hierophants, rather than Wizards.

The religion of the Light Wizards is somewhat vague and esoteric, in that Hysh is a symbolic representation of a force more than a distinct entity, and it somewhat complicates their world view in that various practitioners of the dark arts (including even the Skaven!) are just as capable of using spells of Light Magic as the faithful are. The "perfect" form of the pyramid features heavily in the construction of Temples of Hysh, and arrangements of acolytes in their ceremonies; the most powerful spells of the Light College are focused on the energies of the earth. This faith is almost exclusively limited to small followings in Araby, and to Light Wizards.

THE LADY OF THE LAKE
The Lady of the Lake is the goddess of the state religion of Bretonnia, much celebrated in the practices of the orders of knights who seek out the Grail. Unlike many religions, the Lady of the Lake does not impart any miracles or spellcasting upon her adherents, and there are many who suppose that perhaps the Lady of the Lake is not a real goddess at all, but merely represents a great deal of wishful thinking on the part of romantic Bretonnian Grail Knights. Nonetheless, most Bretonnians offer up prayers to her, Grail Knights claim to receive visions in dreams from her on the whereabouts of the Grail, and the Damoiselles du Grail are healers who act in her name.

The symbol of the Lady of the Lake is the Grail, though it is generally only worn by the Damoiselles du Grail and the Grail Knights who have (purportedly) succeeded in their quests to find the Grail. Questing Knights still seeking the Grail (and those most likely to be adventuring Heroes) wear the Fleur de Lys instead, as a symbol of their quest. The Lady of the Lake is considered a goddess of honor and chivalry, protection of the innocent, favoring the brave and punishing the dishonorable, though peasants grant her far wider-ranging powers, such as the ability to bless crops, purify springs of water, and so forth.

SHALLYA
This is a lesser religion, found only in Couronne in Bretonnia, where can be found rivers to which are attributed healing powers. Priestesses of Shallya are healers, known as Sisters of Mercy, who tend to the wounds of common people. There is some mild rivalry between followers of Shallya and the Lady of the Lake, but also a mutual respect.

MORK AND GORK
Mork and Gork are the twin brother gods of the Orcs -- and, by extension, the rest of the Goblinoid races. They are brutish gods of war, and their powers and blessings are devoted to that notion, as manifested in their shamans, who employ the power of the Waaagh!. Mork and Gork are generally not recognized by other religions as being actual deities (or at least not major ones), but it is often supposed that they are merely manifestations of the strange magic of the Orcs -- simply because the Orcs believe in "Mork" and "Gork". Mork and Gork demand no particular tenets of their followers -- Indeed, the Goblinoids freely abuse and even eat each other when the mood strikes -- but only seem to value raw strength and power.

CHAOS GODS
There are many Chaos Gods, though only a few of them are powerful enough to have any particularly large following: Khorne, Slaanesh, Tzeentch and Nurgle. These entities live within a realm known as the Warp, and have numerous magical creatures under their command, known to mortals as "daemons". Daemons can only live off of large amounts of magic, and thus can only enter into the mundane world for limited time periods -- prolonged separation from realms of chaotic magic will cause them to waste away and eventually dissipate altogether, and the Chaos Gods themselves cannot even enter the physical realm -- though their followers believe that when all of the Warhammer World falls to Chaos, the Chaos Gods will be able to tread the physical world freely.

Slaanesh, Tzeentch and Nurgle grant spells to their followers, and all of the Chaos Gods grant their followers various "blessings" that represent their "evolution" from mere mortals toward the ultimate goal of becoming immortal daemons. Precious few (if any) survive the process. These Chaos mutations are quite often debilitating, but sometimes offer various powers, such as increased strength, resistance to disease, and such -- but it more often forces cultists that have found "favor" with the Chaos Gods to hide their deformities, or to flee civilization altogether.

The powers of the Chaos Gods are strongest in the northernmost polar wastelands, where reality itself has been warped, and normal living things will either be mutated beyond recognition or utterly destroyed. They have several adherents serving in secret in the societies of humans and the Elder Races, and openly amongst the Chaotic Hordes to the north.

KHORNE
Khorne is known as the Blood God, a god of war and destruction. He is depicted as a dragon-winged, dog-headed, muscular humanoid in brass armor, and the battle axe is considered his (un)holy weapon, and is thus favored by Chaos Warriors that pledge allegiance to him. He alone of the major Chaos Gods grants no spells to his followers, instead showing his favor by granting them superhuman strength and various mutations. Many of his daemons, despite being of an inherrently magical nature, have resistance to most forms of magic.

Khorne favors might and martial prowess, and despises sorcery; he is known to possess a bizarre code of honor, such that many warriors of Khorne will find it beneath them to slaughter unarmed innocents, but eagerly seek out all armed warriors to do battle with them. A valiant warrior who defeats one of Khorne's champions, despite being surrounded by countless minions, may unexpectedly find that Khorne has granted him free passage, and a chance to live ... for now. Witch Elves are also devotees of Khorne, as are the majority of all Chaos Warriors.

TZEENTCH
Tzeentch is known as the Lord of Change (and his major daemons are known by a similar honorific), as a god of sorcery and transformation. He is depicted as a huge fusion between bird and man, possessing wings, a bird-head (or sometimes a bird's skull for a head), and savage claws. Of all the Chaos Gods, he has the most control over the Winds of Magic, and is the most diligent in warping the forms of his followers into "better" (or at least experimental) forms.

SLAANESH
Slaanesh is perhaps the most popular of the Chaos Gods in human society, though known by different names and aspects. Slaanesh is depicted as a hermaphroditic minotaur-like creature with blue hide and an extra set of limbs that end in giant crab pincers. Slaanesh is seen as a god of pleasure and pain ... though the "pleasure" part is more popular.

NURGLE
By far the most repulsive of all the Chaos Gods, Nurgle is depicted as a massive, ridiculously bloated, green-skinned, vaguely humanoid being with long spindly horns sprouting from his head, covered in festering boils, with strange alien innards poking out of torn flesh and spilling foul fluids. He is the god of disease and pestilence, and his followers are "blessed" with various horrific diseases. Those who survive are granted a sort of immunity from disease, and the honor of spreading these afflictions throughout human (and other) society.

THE HORNED RAT
The Horned Rat is the deity of the Skaven race, and sometimes seen by outsiders as a fifth Chaos God, though holding a place lower than the other four -- though the Skaven would certainly not see it this way. (Another thing that they would violently object to, is the idea that the Horned Rat is a manifestation of the collective spirit of the Skaven people, in the same way that Mork and Gork are likely "manifestations" of sheer Orcishness.) The Horned Rat grants spells to his followers, but is also worshipped by them in various "aspects": Plague Priests of Clan Pestilens focus on his aspect as a bringer of disease to wipe out the enemies of the Skaven and the weak among themselves; Sorcerers and Warlock Engineers of Clan Skryre see him as a granter of general sorceries.

In any case, he is seen as the creator and champion of Skaven-kind above all other races, a protector of the race as a whole, but merciless to individuals who are not "worthy" -- In a sense, the Skaven who follow different "aspects" of the Horned Rat might be seen as "experiments" by the Horned Rat in his goal to strengthen the Skaven race. Whomever emerges victorious in these internal clashes will find out that they were his true followers all along.

The Skaven may occasionally ally with forces of Chaos, and they seek the downfall of the empires of the humans and the Elder Races. However, they have no particular desire to destroy the fabric of reality itself, and thus followers of the Horned Rat have often clashed with those of the "other" Chaos Gods. Any Skaven character will almost certainly be a follower of the Horned Rat, in one or more of his many aspects.