NetHack/Setting

Character Classes
While not "true" characters in and of themselves, many of the available roles have traits and features associated with them that remain consistent across playthroughs, such as a specific pantheon of gods (with the exception of the Priest, who can serve any of the pantheons at random) and a unique set of abilities and features.

Archeologist
"Archeologists understand dungeons pretty well; this enables them to move quickly and sneak up on the local nasties. They start equipped with the tools for a proper scientific expedition."

- A Guide to the Mazes of Menace: Guidebook for NetHack


 * Adventure Archaeologist
 * Character Alignment: They can either be lawful or neutral.
 * Dual Wielding
 * Fragile Speedster: While they tend to start with low strength and aren't exactly the most combat-ready class at the beginning, their intrinsic speed and stealth lends themselves a lot to hit-and-run tactics that can carry them a long way.
 * Mayincatec: The theme of their pantheon.
 * Whip It Good: One of their starting weapons is a bullwhip.
 * Why Did It Have to Be Snakes?: Invoked - their quest branch's monster generation is heavily skewed towards all sorts of snakes.

Barbarian
"Barbarians are warriors out of the hinterland, hardened to battle. They begin their quests with naught but uncommon strength, a trusty hauberk, and a great two-handed sword."

- A Guide to the Mazes of Menace: Guidebook for NetHack


 * Acquired Poison Immunity: Barbarians start the game with this, increasing the availability of options for food.
 * An Axe to Grind: Starts the game with one. Cleaver is an artifact battle-axe that acts as their first sacrifice gift.
 * Barbarian Hero
 * Dumb Muscle: Subverted - they have the same capacity for intelligence as other player characters, but have a high spellcasting penalty and start with low wisdom and intelligence stats - not that they suffer for it.
 * Unskilled but Strong: Shares this with the Valkyrie - both are heavily combat-focused classes that have heavy spellcasting penalties but can easily get by on stellar armor and weapons, and the barbarian also has the additional boon of starting with intrinsic poison resistance.

Caveman
"Cavemen and Cavewomen start with exceptional strength but, unfortunately, with neolithic weapons."

- A Guide to the Mazes of Menace: Guidebook for NetHack


 * All Cavemen Were Neanderthals: They even have neanderthals as quest guardians.
 * Carry a Big Stick: Clubs are their weapon of choice, and their quest artifact, the Sceptre of Might, is a mace.
 * Difficult but Awesome: Cavemen are considered a "harder" variant of the Valkyrie - a combat-oriented role with no real use for spell-casting, but they also cannot use most edged weapons without receiving them as sacrifice gifts; their starting club is also a piss-poor weapon in general. However, multishot spears at Expert skill can do absurd amounts of damage, and the aklys upgrade in 3.6.1 make it a stellar weapon for most of the game. Their lack of cannibalism penalties makes food less of a problem later on, and their quest artifact, The Sceptre of Might, is also considered one of the best in the game for its ability to invoke conflict.
 * I'm a Humanitarian: Cavemen can eat monsters of the same race as them with no penalty; among other things, this makes tine of nurse meat far more beneficial compared to other classes.
 * Noble Savage: Cavemen can be lawful or neutral, and many of their role's aspects are drawn from this (e.g. Shaman Karnov, the quest leader).

Healer
"Healers are wise in medicine and apothecary. They know the herbs and simples that can restore vitality, ease pain, anesthetize, and neutralize poisons; and with their instruments, they can divine a being's state of health or sickness. Their medical practice earns them quite reasonable amounts of money, with which they enter the dungeon."

- A Guide to the Mazes of Menace: Guidebook for NetHack


 * Combat Medic: Can serve as this with some luck in finding and training with early weapons that they can master. Staves, knives and unicorn horns in particular (often used to cure Standard Status Ailments) can be trained to Expert.
 * Classical Mythology/Greek Mythology: NetHack Healers are styled after classical-era doctors (e.g. humour theory is still in practice), and their pantheon consists of Greek gods, with a Cyclops serving as the quest nemesis.
 * Crippling Overspecialization: Healers excel at healing spells, but are restricted in all other spell classes and tend to lack any real offensive options in the beginning. Downplayed somewhat in that it doesn't cut them off from casting them completely, merely restricting the amount of benefits they can expect from such spells - magic missile is still plenty powerful in their hands, for example.
 * Instant Sedation: Healers start with a wand of sleep.
 * Useless Useful Spell: Cure sickness, their special spell... which cures sickness (and also sliming).
 * Boring but Practical: It's also the only such means of curing sickness that can be made 100% reliable, since even blessed unicorn horns may fail occasionally.
 * Weak but Skilled: Healers start with little in the way of armor, food, and weapons, but with care and diligence can still make it a few levels - enough to gain reliable access to the stone-to-flesh spell (which can easily solve any food related problems for the entire game). Their starting cash and stethoscope can be used to sniff out or purchase solid armor and weapons, and their healing abilities and items allow them to reliably stay alive and support their pets well (especially for protection rackets and/or Pacifist Runs).

Knight
"Knights are distinguished from the common skirmisher by their devotion to the ideals of chivalry and by the surpassing excellence of their armor."

- A Guide to the Mazes of Menace: Guidebook for NetHack


 * Blade on a Stick: Knights always start with a lance.
 * Chess Motifs: Knight have a special intrinsic jumping ability that lets them move like actual chess knights, though with the restriction of not having their path obstructed.
 * Cool Horse: The Knight always starts with a saddled pony and food primarily meant for it.
 * The Code: Knights are expected to adhere by an in-game code of chivalry, and penalizes them in particular for overeating, stealing, and using poisoned weapons, or else attacking immobilized or fleeing foes.
 * Excalibur: Their first sacrifice gift.
 * Heroes Prefer Swords: Knights start with a long sword.
 * Knight Errant in Shining Armor
 * Lightning Bruiser: Combining their lance with the speed of their mount allows Knights to joust and pound several enemies to death, potentially before they can actually get a hit in.
 * Mounted Combat: The Knight excels most at this among the playable roles.
 * The Paladin
 * Turn Undead: In special role ability and spell form!

Monk
"Monks are ascetics, who by rigorous practice of physical and mental disciplines have become capable of fighting as effectively without weapons as with. They wear no armor but make up for it with increased mobility."

- A Guide to the Mazes of Menace: Guidebook for NetHack


 * All Monks Know Kung Fu
 * Bare-Fisted Warrior Monk
 * Canon Immigrant: The Monk role was imported from SLASH'EM.
 * Enlightenment Superpowers: Of a sort - Monks actually exercise wisdom by going hungry. Their quest artifact, the Eyes of the Overworld, also gives them 'astral vision'.
 * Shaolin and Wu Tang: Styled after the former, with a Chinese-themed pantheon.
 * Simple Staff: One of the few weapons they can actually take skill levels in.
 * Useless Useful Spell: Restore ability, their special spell (with the spellbook being their crowning gift) can restore lowered stats... and so can unicorn horns for absolutely no cost in magic power. And unlike the potion, the spell can't restore lost levels. <--In 3.7, the nerf to the unicorn horn's healing ability makes this spell more useful.-->

Priest
"Priests and Priestesses are clerics militant, crusaders advancing the cause of righteousness with arms, armor, and arts thaumaturgic. Their ability to commune with deities via prayer occasionally extricates them from peril, but can also put them in it."

- A Guide to the Mazes of Menace: Guidebook for NetHack


 * Carry a Big Stick: Priests start the game with a mace.
 * Church Militant: Of the "blunt weapons" kind.
 * Detect Magic: Priests have the innate ability to recognize if an item is cursed or blessed.
 * Turn Undead: In special role ability and spell form!

Character Alignment
The game allows player characters to be one of three alignments: Lawful, Neutral, and Chaotic. There is no good/neutral/evil axis as such: the game instead tracks players' "alignment record", which in essence is an indicator of one's standing with their respective god; despite Everything Trying to Kill You, the only unambiguously evil characters are "unaligned" ones, with unaligned altars belonging to Moloch. While the gods themselves and their pantheons are fairly interchangeable, each alignment's god has their own expected code of conduct from the player, albeit a fairly loose one.