On Pigs

Now there were nigh unto the mountains a great herd of swine feeding. And all the devils besought him, saying, Send us into the swine, that we may enter into them. And forthwith Jesus gave them leave. And the unclean spirits went out, and entered into the swine: and the herd ran violently down a steep place into the sea, they were about two thousand, and were choked in the sea.

- The Gospel of Mark

We sacrifice unto Mithra, the lord of wide pastures, ...sleepless, ever awake;
Before whom Verethraghna, made by Ahura, runs opposing the foes in the shape of a boar, a sharp-toothed he-boar, a sharp-jawed boar, that kills at one stroke, pursuing, wrathful, with a dripping face; strong, with iron feet, iron fore-paws, iron weapons, an iron tail, and iron jaws

- The Mehr Yasht

Boars are holy beasts, the favored mounts of the gods. With their glorious tusks, iron-like hooves, supernatural abilities to hear and smell, incredible strength, natural beauty, it is no wonder why the divine favors boars. Great golden chariots pulled by hulking hogs are a common feature in paintings and carvings of scenes from myth. In the wild, boars grow almost unendingly, with valley peasants fearfully shouting about a great swine-god they saw looming over the mountains in the moonlight. It is against the law for those outside of the priestly and noble castes to hunt and kill wild boars above a certain size (in many valleys, regular boar hunts are performed for the exact purpose of making sure that boars never grow above a given size and so the people may hunt them without fear of retribution, though a significant portion of the product of such hunts must be handed to priests in sacrifice). This is not unlike the prohibition for commoners to harm lions, the king of beasts.

Boars are half-spirits, for they exist half in the world of flesh and blood and half in the immaterial spiritual world. Their eyes can see both worlds simultaneously, unlike humans whose souls are trapped in physical bodies until death. Domesticating a boar, chaining its body and sculpting it to your whims, is intensely taboo. It severs the boar and all their children and their children's children from their spirit halves. It perversely tears the rightful property of the gods from their holy hands. It is a selfish act, and good virtuous people do not do it. Well, that is what the priests say when they see the outcast, the foreigner, or the sorcerer tending to their herd of swine.

Due to their unique place in the cosmos, clerics interact with boars and pigs in unique ways.

(As an aside, though I will probably describe this in more detail in future: clerics are conduits of spirits (clean, unclean, truthful, dishonest), mostly mystery initiates into given cults or wise women and wise men from villages.)

Clerics are able to calm or intimidate wild boars and turn domesticated pigs using the turning rules. The nature of turning differs for truthful and untruthful (lawful/chaotic) clerics, for the heavenly and chthonic gods differ in their desires and natures, though both groups of gods despise domesticated pigs.

Turning Results:

Heavenly (Truthful/Lawful)            Chthonic (Untruthful/Chaotic)

Turn/Destroy Undead                     Impress/Control Undead

Calm/Befriend Wild Boars              Intimidate/Cow Wild Boars
Turn/Destroy Domesticated Pigs

Since the flesh of the pig is so malleable and they lack the strong souls of other creatures, domesticated pigs are a favorite of sorcerers. One such creation derived from the pig is that of the pigman, a pig twisted to stand on its hind feet, with an alchemical concotion instead of a brain. These are made by alchemists and wizards, and although pigmen are associated with such fringe magic-users, they are not uncommonly created to be put into service for a sorcerer's client, sometimes even a priest who may normally rail against swine-magic.

Pigman

Stats as Orc

Caravans and Brigades: When encountered as a wandering monster in the wilderness, the pigmen will be guarding either a caravan containing treasure traveling from point A to point B, or they will be marching with their leader.
Leader: A group is led by a pigman with maximum (8) hit points and +1 to-hit. These are the higher ranking pigmen in service of their creator.
Magical: Pigmen always detect as magical, although they typically cannot cast spells.
Non-Porcine Leadership: The ultimate leader of a band of pigmen is never a pigman themself. Typically they are a high level magic-user, cleric, or higher hit die humanoid monster.
Servile: Pigmen are typically magically conditioned to serve a singular master. If this magical conditioning is bypassed, they typically will not fight.
Turning: Although they are made from pigs, pigmen cannot be turned by clerics, due to their false alchemical minds.
Weapons: Typically axes, clubs, spears. Higher ranking individuals will wield swords and missile weapons.

(The pigman is kind of just an orc replacement, specifically calling back to the orc from the original Little Brown Books, if the references to non-orcish non-porcine leadership and guarding caravans of treasure wasn't very obvious...)

Pigmen in service to an especially cruel sorcerer, priest, warrior, etc will oftentimes be found riding another strange and horrible creation... the manpig, a crouched and corpulent human with the mind of a pig, lacking the thought processes of a human and the life of a human. They are rather slow creatures, but wild boars kill pigmen almost on sight and the twisted forms of the pigman are uncomfortable on horseback. Camels are ridden too, at least in desert environs and for long distances, but in shorter distances cruel pigmen ride manpigs.

Manpigs are created in a ritual where a human mind and spirit are trapped in the body of a pig, while the pig's mind is brought into the human's body. There are numerous ways to fix this mindswap, but the most reliable is to perform a counter-ritual with both the pig possessed by the unwitting human and the manpig present. High level clerics are able to simply undo the sorcery by turning a manpig. Sometimes, the magic-user which created the manpig perishes and there is noone to switch the pigs and humans back, or the pig with the human mind trapped in it dies of its own accord. When such a state of affairs has passed, the ritual cannot be performed, and manpigs with no master will act as they wish. Oftentimes, they will eat the wizard that created them and then crawl out into the wilderness, rooting through the mud for roots and mushrooms, though wild boars will kill them on sight in disgust.

Manpig
Armor Class: 12
Hit Dice: 2 (9)
Attacks: 1 x bite (1d6+1 and disease)
To-Hit: +1
Movement: 150' (50')
Saving Throws: D12/W13/P14/B15/S16
Morale: 9
Alignment: Chaotic
XP: 25
Number Appearing: 0 (0)

Disease: The bite of a manpig carries a rotting disease. When bitten, the target must make a save vs. poison or contract a slow-acting rot that steadily makes the part of the body bitten pained and unusable. The character must be healed magically or with a special poultice for the disease to be cured.
Domestic: Not encountered in the wild. Typically ridden by pigmen or created by sorcerers.
Melee: When in melee, both rider and mount can attack.
Turning: Although they are not physically pigs, manpigs can be turned by clerics.