I am posting what is a fairly simple Orc lair for levels 1-3. The rules used are 5th Edition Dungeons and Dragons but certainly, it can be modified to just about any fantasy ruleset. I have not included statistics for the monsters. Standard 5th edition statistics was assumed.
Red Fang Lair
An orc lair not far from human lands has encountered a deadly problem. The orcs are dying and desperate. This is good right?
Forty years ago an alchemist of dubious reputation set up his secret work area not far from the town of Daggerford. Otrava chose a set of caves beneath a rocky hill. Far enough from civilization so as not to be disturbed but close enough to allow him to get supplies.
Otrava needed the seclusion because he was laboring in the service of Talona, goddess of disease and poison. He was developing a magical artifact that could spread a toxin on command through the air, the Icon of Talona.
When Otrava had completed the icon he needed someone to test it upon. As if by divine intervention a tribe of orcs moved into the caves. The orcs were a small warband separated from the main tribe. The settled into the caves and began raiding nearby human settlements.
Death began to stalk the orcs in their lair. One of the first to go was their Warchief. The orcs began to realize where the danger areas were in the caves and moved to safer caves near the entrance. Without a war chief to lead them, a few of the orcs fled on their own. Those that remain know their numbers are not strong enough to safely make their way through human controlled lands to their ancestral home.
Otrava had planned to kill all of the orcs. But his creation was not powerful enough and the orcs could not be intimidated into leaving. Otrava worked feverishly on the artifact attempting to make it more deadly. In doing so Otrava miscalculated and exposed himself to the toxins. He died with a look of surprise on his face.
The job board in Daggerford has a posting asking for adventurers to remove an orc lair not far from Daggerford.
There is a clear trail leading up to the Orc lair. The orcs have not taken any effort to hide their lair. Two large circular stones stand to either side of the entrance. These provide cover to javelin throwers if they are under attack and can be rolled over to block the entrance if necessary. Because of the depleted numbers of the tribe, there are no guards outside the entrance.
(2). Vigilant guard
There is an orc stationed in this alcove just inside the tunnel to the orc lair. The orc is alert making him difficult to surprise. He will bellow loudly if he spots more than 2 intruders (fewer and he feels he is capable of handling the threat on his own). If he yells out, the orc at area 3 will arrive in 2 rounds. The orc has 5 copper coins.
(3). Sleeping guard
There is an orc at this alcove just off the main tunnel. He is currently dozing but will be awakened by noise from area 2. The orc has 12 copper coins.
(4). Main Cavern
The tunnel leads into a very large cavern. A ledge (10 feet high) divides off the eastern side of the cavern. To the north, a tunnel leads up rough-hewn steps. To the south, there are two tunnels leading down rough steps. In the northwest corner of the cavern, there is a 15 foot in diameter pool of fresh water. The water must be replenished by a spring because it is clear and not stagnant. The pool is 12 feet deep. The roof of the cavern is 20 feet high.
If intruders have made it this far without making a lot of noise, there will be three female orcs filling sacks with water at the pool. They will fight with daggers if approached. If possible they will flee to area 6 to get help.
If the orcs have been alerted to intruders there will be 8 orc warriors and Breka (see area 5) waiting in the chamber. Four of the eight orcs are armed with javelins and will be atop the ledge to the east.
(5). Sub-chiefs lair
This area is now the sleeping area of the sub-chief of the Red Fang tribe. There is not much here, a pallet of straw and furs to sleep upon, a wineskin, and some raw meat. Hidden in the sleeping area is a purse containing 20 gold coins and 200 silver coins.
The second in command of the Red Fang tribe of orcs was Breka. He has taken command of the tribe now that the war chief is dead. He is treated as a normal Orc for statistics. Has lack of warrior skill has caused his leadership to be challenged and several orcs have run away. Breka makes up for his lack of warrior prowess with his uncommon wisdom. He will look at intruders in the lair as an opportunity. If given the chance he will request a parlay. If adventurers agree to the parlay, Breka will explain that something to the northeast is poisoning the tribe. He will ask that the adventurers help out the orcs by destroying whatever cursed object or creature is causing the poison. He can tell adventurers that the poison is gradual so they should have plenty of time to investigate. In return, the orcs will not attack or harass the adventurers as long as they stay out of areas 5 to 9. If the adventurers are unconvinced, Breka is willing to pay them 20 gold coins.
(6). Orc Warriors
The remaining orc warriors of Red Fang tribe sleep in the cave. The cave has a sandy floor and spread around on it are ten straw pallets for sleeping upon. If the adventurers have achieved complete surprise there will be 8 orcs resting in this area. Each orc has 1d20 copper coins and 1d6 silver coins. They are armed with great axes and javelins. Two of the orc warriors are female.
(7). Orc Sleeping area
This cave has a sandy floor and there is a cooking pit in the center of the cave. In the pit are burning hot coals and wood. Above the flames is a large cauldron. Smoke from the fire escapes through a natural chimney in the roof of the cave 12 feet above. Pallets of grass and leaves mark sleeping areas. There are four female orcs here tending the fire and five young orcs. A stew of racoon meat is bubbling over the fire.
The female orcs will fight to defend the young orcs. Treat the females as regular orcs and the children as non-combatants.
Several sides of beef and various skinned deer, raccoons and even squirrels hang from hooks pounded into the ceiling of this low (7 foot cave). The beef is from cows stolen from human farms in the area.
Five wooden crates are stored in this chamber. All have been opened. In the crates are blankets, human clothing, and metal utensils. The crates are marked “Daggerford”.
Effects of the Icon of Talona
Once adventurers leave area 4 and move north or east they enter the area filled with the diluted toxin from the Icon of Talona (in area 19). The toxin is odorless and colourless so it is unlikely to be noticed. Every two turns adventurers are in this area have them roll a DC10 Constitution saving throw. On a failed save they take 1 point of damage (no damage on a successful save).
(10). Abandoned Barrack
This cave has a smooth stone floor. There are twelve simple wooden beds scattered about the cave. Two beds are flipped on their side. A dead orc lies face down in the center of the cave. The orc has been dead for about a week and has no signs of violence on him.
(11). Abandoned Kitchen
This cave has a simple stone oven against the north wall. Piles of chopped up firewood and two large, wooden tables. Rotten food (meat and vegetables) rests on the tables. The secret door is next to the oven on a flat part of the cave wall.
(12). Garbage heap
Piles of bones and rags are tossed into the narrow cave. The cave is also the home to 4 Giant Rats. In amongst the bones are 6 gold coins.
(13). Council Room
This cave has a dozen wooden stools arranged in roughly in a circle. Three dead orcs lie on the floor of the cave. There is not a sign of violence on the orcs but they have been dead for days.
(14). Death from Above
This is a large cavern, the ceiling bristling with stalactites. There are also four large stalagmites in the eastern end of the cave concealing a secret door. There are four Darkmantles clinging to the ceiling in this cave (20 feet up). They will drop down on unsuspecting adventurers.
(15). Refuse dump
Just inside this cave, the floor gives way, dropping ten feet into a large pile of food and biological waste. The smell is noticeable as soon as the tunnel leading to the cave is entered. If adventurers stand on the ledge and observe the pile of refuse they will spot occasional movement. This is the movement of 6 giant centipedes burrowing under the garbage. They will only attack if disturbed. It is possible that heroes might mistake this garbage as the source of the toxin in the air. Even a thorough search of the garbage will find nothing.
(16). Dripping cave
This cave is dripping with moisture which has covered the floor with a film of water. The walls of the cave are coated in strange, glowing green moss. There is a clear patch on the south wall that is dry. Examining the floor in this area will reveal scratches in the stone left by the secret door that open outward. There is a pit dropping 20 feet down in a small alcove in the north end of the cave. The pit is only 3 feet in diameter.
(17). Unlucky adventurer
In a small cave, there is the skeletal corpse of an adventurer seated against the north wall of the cave. A broken sword is clutched in one hand, the blade nowhere to be found. In his pack are mummified rations and a pouch containing 200 silver coins and 20 gold coins.
(18). Spider Lair
This cave appears empty except for a broken blade lying on the ground and what appears to be the jawbone of an orc. If adventurers look up they will see a ceiling of webs 15 feet above their heads (the actual stone ceiling is 20 feet above). Crawling about in the web are 2 giant spiders.
(19). The Alchemist's Lair
The secret doors lead to a stone chamber. The walls are carefully fitted stone blocks, the floor flagstones, and the ceiling is stout oak timbers. The chamber is dark but there are four unlit lanterns on the walls that could be relit. In the center of the room, there are two large wooden tables cluttered with books, papers and glass bottles and vials. In the southeast corner, there is an unmade, human-sized bead. A small end table beside it with an open book on top of it. Several cloaks hang on hooks near the bed. There is a backpack resting on a small table against the west wall. In the backpack are two jugs of wine and six packets of rations (unspoiled). Finally, in the north east corner of the room, there is a 5 foot in diameter stone platform 2 feet tall. Resting on the platform is a curious looking crystal statuette of a demon with its fanged mouth hanging open. Just beside the stone platform is a dead man lying on the floor. The man is wearing a heavy cloak, leather gloves, curious glass lensed goggles and a plague mask (a cone shaped mask that covers the mouth).
The Icon of Talona
The statuette is the Icon of Talona. If a character gets close to the icon they can see an almost invisible mist pouring from the icon’s mouth. While characters are in area 19 they need to make a Constitution save against DC10 every turn. If they fail they take 3 points of damage. If they pass they take 1 point of damage. The icon will continue spewing toxin into the air until the command word is used to stop it. The command word is in Otrava's diary but it is written in infernal. The icon can also be destroyed casting Dispel Magic on it at level 3 or by doing 10 points of Bludgeoning damage to it (which will cause it to shatter).
The Alchemist Otrava
Otrava the specter will appear if any damage is done to the Icon or if it is moved. He will furiously attack intruders. Otrava's rage at the manner of his passing has turned him into a specter. It is Otrava’s body lying on the floor killed by his own creation. His mask is a magical mask of protection which reduces the effects of the icon to 1 point of damage in this room and no damage in the rest of the caves. There is nothing else of interest on the corpse.
In the alchemy lab, there are many items of interest. In an opaque jar, there are 7 red gems (7 x 50 gold). One of the many vials is a potion of growth. Resting amongst a number of clay pots is an Alchemy Jug. The book on the nightstand is Otrava's diary, it is written in infernal. It details the experiments that Otrava has been performing. Under the books is a small pouch holding 45 gold coins. Four of the books spread about on the tables are valuable (4 x 150 gold coins). There are also 12 vials of poison resting on the tables.
If the adventurers succeed and head back out of the caves, the orcs will be waiting in area 4. Unless provoked, Breka will allow the adventurers to pass. Breka can also be convinced that it would be best for the Red Fang tribe to find a new hunting ground further from Daggerford.