Orcs are generally portrayed as monsters. Usually, they take the role of the big, strong, but wholly evil and ugly cannon-fodder for the Big Bad. The Lord of the Rings originated the term as we know it, although other continua have included orcs and even made their own varieties and modifications. If an orc agent is encountered, it is not safe to treat them as you would another orc variety. It is likely they would take very great offense. And one trait nearly all varieties of orc share is that you really, really do not want to make one angry.
Mixing up any of these orc types or substituting one for another is a charge if you want it to be.
Not closely related to Random Orcs, which can be of any species (including orcs).
Tolkien himself never confirmed the origin of the orcs (he was unsettled by the spiritual implications of their possible origins), but the most widely held theory is that orcs were once elves, but through Melkor's twisted machinations they were corrupted into a race of stunted, unclean, savage, and wholly evil humanoids. They appear as the minions of Sauron and in Saruman's army of Isengard, making up the brunt of enemy forces. They care little for nature, or really for anything but themselves at all, going so far as to quickly become cannibals when hungry. Tolkien's orcs are wild and chaotic when unaffiliated, but Mordor and Isengard are cruel to the extreme in making them into an army. Weapons of orc craftsmanship are shoddy — and in the case of the orcs of Isengard, mass-produced.
In The Hobbit, the terms 'orc' and 'goblin' are used synonymously, though in Lord of the Rings, they appear to be slightly different. Also, in Lord of the Rings, Saruman develops a larger, stronger breed of orc called the Uruk-hai.
Warcraft orcs play straight the combative, chaotic model of Tolkien orcs, yet also switch it up a little. Although they are prone to hunching, Warcraft orcs are as tall as or even taller than standard humans, but also much more muscular, with thick wrists and green skin. Interestingly, the green skin is a remnant of previous demon corruption, not a natural adaptation.
Before the demons' interference, the orcs were a shamanistic (if still confrontational) people on their home world of Draenor. The demon army, called the Burning Legion, fooled them into pledging their services for power, and they were let loose on the land of Azeroth to rough up the inhabitants prior to a demonic invasion. It did not work. Twice. Currently, they are free from their corruption, but face a harder task of learning to be a people again, and to make an identity out of what was once reduced to merely an army. Although their culture makes them prone to being violent, they do not see anything wrong with that — and they are as likely to be as just as a human is likely to be just. And as cruel as a human is likely to be cruel.
Warcraft orcs mix a love of fighting and a value for physical prowess with an uncomfortable past and a reverence for their ancestors and the elemental spirits. A Warcraft orc can be anything from a hot-headed bully to a wise spiritual seer.
Dungeons & Dragons Orcs
Dungeons & Dragons orcs resemble Tolkien orcs in that most are evil, sharing the same unclean, wholly unreasonable, and hostile portrayal. There are sects and varieties in individual settings or campaigns that are not hostile, but that depends on if your DM decides to include the specific expansions they are in, or prefers orcs as a simple beat-em-up mob enemy.
They are one of the common foes many adventuring parties fight, and there are orcs hailing from almost every biome or magical plane, and enchanted variety you could ever imagine. Yes. Even aquatic orcs. Believe it.
They have apish features but slightly more human proportions, lupine ears, and a sickly grey pigmentation to their skin. Their intelligence is said to be lower than normal, but some people interpret this as an extreme difference in cultural values.
Half-orcs are a commonly playable race. The origin of these few crossbreeds can be a tale of a very unlikely romance... or pure nasty squick.
These are somewhat similar in role to Dungeons & Dragons orcs in that they are a strength-oriented, savage people. However, their physiology is drastically different. Their hides are green and extremely wound resistant, and they reproduce asexually — all of them are referred to as 'he.' Their metabolisms are bizarrely adrenaline-based: The more and tougher battles they fight, the larger and stronger they become. They also refuse to make any sort of alliance and are actually just as likely to fight among themselves as they will an outside foe. They are supported by all sorts of war machines.
They draw power from 'The Great Green' or 'WAAAAAGH!' as they call it. This is also their battle cry. It always is in all caps, always contains three or more As, and is one of the acceptable places to put multiple exclamation points.
Like so. Deyz awlzo speaks like dis. Dey just do. Dey gots da talks in deir blood.
Warhammer 40K Orks
These are similar to the fantasy setting Warhammer orcs, except with a 'k' and IN SPAAAAACE. Actually, more accurately, they swap out magic and swords for firearms and black-powder projectiles, as well as stickbombs. They do wear helmets and such — resembling WWI German paraphernalia when it doesn't appear to be randomly cobbled together from scrap metal. Like their fantasy kin, they reproduce asexually and share a genetic blending to fungi. They were genetically engineered as living weapons by a long-since extinct alien race called the Old Ones in order to fight the Necrontyr (later the Necrons) and were designed to survive in any environment; because of this, there are more Orks than any other race in the galaxy. The spores they emit have a terraforming effect, creating entire ecosystems designed specifically to support large Ork populations. A particularly unique feature of the Orks is the gestalt psychic field they generate, called the "WAAAGH!". This psychic field is powerful enough to defy the laws of physics and common sense: if you gave an Ork a stick and convinced him it was a gun, the stick would become a functioning gun. The stick will still act like an ordinary stick to anyone else, but to the Ork, the stick will act like a gun because the Ork thinks it's a gun. The more Orks there are in a given area, the stronger the effects of the "WAAAGH!" will become.
They favor repeating weaponry — the larger and faster the hail of bullets, the better. According to them, 'Youz never has enuff Dakka.' Aiming their weapons is an alien concept to them. If you fire enough bullets, one of them will hit its target eventually, right?
And yet again,
Magic: The Gathering Orcs
Orcs in Magic: The Gathering bear many similarities to the Tolkien and D&D orcs they are modeled after. They are large, nearly always have green skin, and have war-based cultures, aligning with Red mana in the color wheel. They are very similar to Goblins, with the main differences being size and cowardice—while Goblins will charge blindly into an impossible battle, Orcs will run away rather than risk an evenly matched fight. This is probably related to the tendency of Orcish commanders to sacrifice troops for short term advantages. Orcs also use other races to their benefit; tenuous coalitions with their Goblin rivals are surprisingly common, and Orcs also train Orggs to fight alongside their distant cousins. Orcish clans tend to get involved in aggressions with Humans or Dwarves.
Orggs are a cross-breed between Orcs and Ogres. They are large and extremely powerful and violent, but also extremely stupid. They can, however, be trained, either by armies of Orcs or Goblins, or by wizards or Planeswalkers.
Orcs have essentially been retired as a supported creature type in the game of Magic, being too similar to Goblins. They do, however, still appear in novels and short stories on occasion.
Elder Scrolls Orcs
Orcs in the Elder Scrolls continuum are properly referred to as Orsimer, and are, as stated, actually a kind of elf (elves in the ES continuum are referred to as 'Mer'). The Orsimer (or 'Pariah Folk') in their current forms were supposedly created when the Daedric Prince Boethiah defeated the Aldmeri god Trinimac, transforming him into Malacath and his followers into the beastly-looking orcs. It's unknown when this apparent transformation happened, but orcs have been a presence in Tamriel and the Iliac Bay region since the early First Era, and have made a kingdom for themselves in High Rock which they call Orsinium (literally 'Orc-Town') — this kingdom has been sacked and rebuilt many times over Tamriel's history. During the Fourth Era, this kingdom, having been sacked yet again, relocates to between Skyrim and Hammerfell.
Orsimer resemble most orcs in the Warcraft vein in that they're green, very large (generally human size or larger), and physically powerful, with notable tusks and flat noses. Their culture — in which they see themselves as outcasts, just like their god Malacath — is often seen by other races as rough and cruel, but there is great equality among the sexes, and the Orsimer are known as an unshakably brave people who can weather any hardship. While they have been targets of a great deal of racial prejudice in their time, often being seen as just savage monsters and goblin-ken due to their appearance, they have managed to win acceptance through their reputation as excellent craftsmen and brave soldiers, serving with distinction in the Imperial Legion. Orcish soldiers wearing heavy armour and harnessing their berserker rage are considered some of the Empire's very best front-line soldiers.
Orcs in the PPC
The PPC employs agents of all sorts, including a number of orcs of various types. Some of these include: