The Villages of ROTN are a far cry from the vanilla Minecraft village. These villages take aspects from a variety of mod-packs: the guards and Village Lord are from Toroquest, the Plague Doctors that spawn in villages are from the Rats Mod, etc. All in all, they are fully-fledged towns that can help an early-to-mid-game player survive and prosper.
In spite of Rebirth of the Night being in 1.12.2, the villagers in this mod-pack resemble those of 1.14 and beyond with added features: similar skins, same roles, similar trades, etc. ROTN villagers do not use workstations like their 1.14 counterparts, but some of the workstations are present (e.g. Cartography Table).
Plague Doctors spawn in witch-like huts in the village. Their chests often include items from Rats Mod: spoiled food, Plague Leeches, Treacle, etc. The Plague Doctors themselves seem to exuberantly priced, in both buying and selling: while one doctor might offer 20 emeralds for a Plague Leech, they might also try to offload some Sweet Smelling Herbs for 17 emeralds! If they progress far enough in their trades, they can sell Golden Apples and Purifying Potions (Can cure the Plague or de-zombify a villager).
These fellows are a rare occurrence in villages, but can offer interesting trades. Unlike most villagers, these only trade in Sapphires, a gemstone found in the deep like most. Their offers are snow-based, but can provide decent trades if you can get the gemstones in hand. While only one or two spawn in regular villages, the arctic wastes can sometimes spawn igloo settlements chock-full of these guys.
These folk are rather strange. Spawning only one or two to a village, these guys only trade in ancient coins, coinage that appears to have fiery origins. Even if one travels to hell and back to get the coins, the trades don't seem worth it: your work only rewards you a "Wrapped Stick" (low-grade Katana) or fossils, which at best can be crushed into refractory material. Perhaps progressing their trades might show something better?
These villagers are quite different from the others you may find. To start, they have darker, bluer skin, wear nothing but yellowish-brownish rags, and in general look closer to an Illager. In spite of this, they are passive mobs, and in fact will run away from the player when approached. In addition to this skittishness, they do not trade, much like Nitwits.
The rest of the odd ones you might find can offer to buy and sell a variety of things: glow-stone dust, ender pearls, bones, etc. They'll usually be dressed in green, but if there's a rat face on their tunic they might offer trades similar to Plague Doctors. It would be appreciated if someone could study these villagers more and further classify them.
Reputation is vital if you want to stick around the town. When you enter a village, you start at 0, but there are multiple ways to increase or decrease this number. Harvesting crops, breaking blocks, and stealing from chests are all ways to reduce your reputation, while planting crops and completing Village Lord quests increase it. If you get to -10 Reputation, you'll be looked down upon by the folk and guards will be more aggressive; make it worse and you could get ran out of town. On the other hand, having a high enough reputation will grant you privileges in the town, whether it be special trades or access rights (you can check your rights by right-clicking the Village Lord).
While the ruined villages at your player's start might have been ransacked, these villages are ripe with valuables for the taking. It should be noted that while popping things off of item frames is fine, raiding chests with villagers (and especially guards) in sight will reduce your reputation and can even get you chased out of town. The same goes for harvesting crops or breaking blocks off of houses, though that is a lesser offense.
The farms are built akin to Vanilla Minecraft, but the crops that grow are much more varied. Not only can the basic crops like wheat and beets grow on these fields, but one can find these fields lush with berries, spices, and even sugarcane!
A good portion of the buildings in these villages will look like those from Vanilla Minecraft. While these don't usually have chests, they will usually contain item frames with some kind of item inside, whether it be raw cod or an iron axe. The larger homes will even have facilities like beds, furnaces, and cake for you to munch down on.
This large wooden rectangle serves as the home of the guards within the village, and is equipped as such. With four empty armor stands, eight beds, and two double-chests chock-full of iron weapons, bows & arrows, and leather armor, this is one of the best places for starting yourself off. Unfortunately, guards and villagers will often be inside due to the presence of beds, making it hard to loot the chests without getting caught.
While it looks identical to its vanilla counterpart, there are one or two differences. For starters, there's a used anvil out in front with a glass item frame containing some kind of iron tool. Secondly, the blacksmith's chest has had its loot table updated to better fit the mod-pack (e.g. Obsidian blocks might now be Obsidian Shard, other iron weapons can spawn, etc.). With the chest in a secluded location, it'll be easy for you to grab & run.
The tallest building of them all, this stone fortress serves as protection from those that might raid the village. If you can get a moment without the guards on the first floor, one can open the two chests to find gold ingots, gold nuggets, emeralds, and sometimes Recruitment Papers (for turning bribed bandits into personal bodyguards). The throne room on the next floor also has plenty of useful blocks to take, but the Village Lord is constantly there, so unless you're trusted enough to break blocks (you can check by right-clicking him), it'd be a bad idea to start breaking apart his quarters.
This is for ROTN 3.0 & beyond: guards are different before then. See Toroquest's Guards if you're playing an older version.
Each functioning village comes with dozens of guards to protect it. While you might not see them immediately when you enter a village for the first time, they'll quickly spawn wherever you look: in the guard towers, the barracks, the Lord's castle, and of course out in the streets. They both look and act similar to the Village Hold guards of Skyrim. To start, if they see you stealing from trapped varnished chests in the town, your reputation will decrease and they will start attack you. If your reputation is negative, they will tell you to lay down your arms and/or attack if you have a weapon in you hand. In terms of equipment, they will carry either bows or some kind of iron weapon - spears, glaives, arming swords, etc.
Somewhere in town there will usually be a gazebo with a bounty board block in the center of it, propped up by a fence post. In this block will spawn Quests over time, which can be completed for varying rewards. The tasks can vary wildly: one might ask for to grab a few bones or kill some zombies, while another might want you to kill a Ferrous Wroughtnaut! Likewise, the rewards are just as varied: anything from a few lumps of coal to a bauble with unique effects. It should be noted that these are timed requests that start when you pick up the paper, though they are scaled with the difficulty of the task.
If you're looking for simpler tasks, the Village Lord is a straight-forward way to gain emeralds and reputation. His requests are simple: he'll usually start by asking you to plant some fields full of crops, but with the right reputation he can trust you to take his diamond pickaxe and go mining underneath the town.
- Fugitive Villagers are usually skittish around players, but will be obedient and follow the player when tied with a lead. They will also stand like livestock if tied to a post. The purpose of this mechanic is for the "Law and Order" quest offered by Village Lords, but handing them in to guards has proven impossible as of 3.1.1a.
- Certain village faculties will not always spawn: the most major examples are the Bounty Board and the Lord's Castle. If the former doesn't spawn, you won't be able to obtain or turn in bounties at that village. If the latter doesn't spawn, it will be incredibly hard to improve reputation for the faction using that village, as no Lord will spawn, preventing you from acquiring quests or bribing the Lord with emeralds & bandit masks. In this latter scenario, only killing mobs in the province will increase reputation, though it will be incredibly slowly over time (~5 hostiles for 1 rep).
- The Village Lord's AI is strangely passive: not only does it not make its way back to the castle if it leaves, but it does not attack hostile mobs, only following them. In general, they slowly wander around wherever they are, and have no AI to return to their throne.
- In the "Law and Order" quest, in order to hand in a fugitive to a guard, you have to (a) have the fugitive tied with a lead, and (b) you have to be holding another lead in your hand. Doing this and right-clicking the guard will remove the villager, the lead it was tied with, and the extra lead in your hand, giving you 1 "Fugitive's Bindings" (or something similar, don't know exact name) for your trouble. While this leads to a net loss of 1 lead per fugitive, it prevents you from losing the originally-named lead that needs to be turned in at the end of the quest.
- In the current and several previous versions, villages may become vast swaths of corrupted chunks that can ruin a single player world. The reason for this is due to the VillageNames mod: updating it to a more recent 1.12 version will prevent corruption, but it changes the village layouts from before.