His Ghastly Song, No Chant of Victory (Two Monsters, Four Areas)

Part of the bandwagon started by Louis and Loch. Use this generator, and make 1d2 monsters in a 1d4+1 area dungeon. 
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I hear that great town Sekahii was wiped off the map, torn down by the fire of the gods. Guess nothing's certain in this bitch age. I'd avoid that cursed place myself, but there are those who would love to know what became of their loved ones, and others who wonder if anything of value survived.

"The only thing strange was that nothing was missing, except all the people."

Sekahii

Ash and fresh stone covers almost everything. Wind has started to reveal the roofs of buildings and the tops of the city walls— those defenses which once repulsed the Tribes of Gale, and which you now step over. In the center of town, the high walls of the temple reach out like a drowning man's hand, and closer, as though grinding against the city wall, is a strange tower, the ash dunes sinking down and leaving the space around it clear. Beyond the town, the fresh-faced Mount Pertumum stares down like a hung-over horse.

• Tower: The Thief's Tower is trying to escape the city but finding itself penned in by the city walls. It has resorted to eating ash. This specimen is four stories tall, with windows on all but the top floor.
• Each floor is decorated with stolen tables and chairs. On the third floor, fine silverware (500 gp)  and a tapestry (1000 gp) hang, saliva having cleaned away any ash that would mar them. On the ground floor, a collection of pottery, jewelry, and hasty sketches (60 gp) lies in rows, the desperate offerings of refugees who tried to escape the eruption into the Thief's Tower.
• Temple: Half-rubble, many ash-stains that once were people. A godstone gilded with gore.
• One ash-stain clutches a set of tablets, a half completed Monster Manual. Experts will recognize this work as a draft by the famed naturalist Tutiksus, literally priceless now that he has passed away. The tablets have information on six "monstros", which range anywhere from an elf to a merchant to a beholder. A player can declare that some creature they encounter is one of the ones described, and consult the tablets about its weaknesses, capabilities, or how to get on its good side. The tablets have a 50% chance of giving specific, correct information and a 50% chance of giving specific, incorrect information.
• Tunnel: Poking out of the mountain, a new, smooth tunnel leads down to the heart of the rock. Here lairs the Aasales, so fumes roll out of the tunnel as she scans for prey.
• Volcano Shrine: Once accessed by a narrow path now-ruined. Now connected to the Aasales's tunnel(, a miracle ordained by the Earth god to ensure people could still worship him.) The shrine of worked iron has been defaced by graffiti— "Tefurus has a long-ass schlong. The Earth God's Schlong is soft and mediocre". There is an ash stain before the altar. If the graffiti is somehow cleared away, the Earth God will bless the suppliant, giving them immunity to lung-based diseases and the ability to safely run over lava and magma.

Bestiary

Thief's Tower

+8 Door (engulf), +4 Stomach quills 1d8. Moves 1 foot/day.

Keystone HD 3, unarmored.

- Furnace Metabolism: It gives off a pleasant aroma, like cooking meat. The result of its alien physiology, it entices victims. On a negative reaction roll, those within 100' must save or try to enter through a door or window.

- Engulf: Those who hesitate to enter outside the door of the Thief's Tower will find it splits in half hamburger-style to swallow them. Save or be swallowed. The door-mouth can be battered down as any stuck door, but see Quills below.

- Leveled Stomach: Though the exterior roughly resembles a constructed stone tower, the inside is clearly a thing of flesh. A Thief's Tower will have 1d4+2 levels, each a stomach chamber lined with walls of undulating quills, bony floors, and cartilaginous, ropy ladders ascending and descending.

- Symbiosis: The Tower will protect those who beautify and enrich it. Bringing in furniture or draping treasure about can give you a well-guarded hideout, the source of the creature's moniker.

- Quills: The quills can carefully push objects around the room, or strike at prey. Each round, it may attack as many targets as it can perceive, and will lunge out of hunger, or to punish those who try to damage it, who try to steal its treasure. The Tower has no vision. It uses its quills to feel and hidden ears to hear what happens within it.

- Keystone: On one floor is the heart-brain of the Tower, resembling an undulating piece of soapstone with veins connecting it to the cartilage and bone. The level that contains the keystone lacks windows.Damaging the keystone, in addition to incurring quill attacks, causes the tower to shrivel up like a juicebox. Save or be thrown off your feet as the tower tilts and wilts wildly, falling prone into a wall and either taking 1d6 damage or losing your next turn (your choice)

Also called a Witch's Tower or Gardinel D'Bologna, the Thief's Tower is a giant cylindrical creature with an eel-smooth, chitin-hard skin. In early spring, it appears in urban areas, the sorts of Gygaxian cities with encounter tables loaded up with vampires and wraiths. Bandits and other monstrous humanoids frequently take advantage of its refuge, and local lords are often slow to address the arrival of a Thief's Tower, as the law usually states that those who slay one are entitled to its treasures, and it's tempting to let it accumulate some booty before you fell it. 

Aasales

HD 6, Unarmored, claw 1d6/claw 1d6/proboscis (see below). Fast as a starving catamount.

- Fume Cloud: constantly giving off black and neon-green volcanic fumes, giving her cover (+4 AC) vs ranged attacks. Breathing the fumes is unpleasant and painful. After an encounter with the Aasales, anyone exposed without PPE has a [round of exposure]-in-10 chance of contracting (and I swear I'm not going out of my way to shoehorn this in) Pneumonoultramicroscopicsilicovolcanoconiosis. Each day, a victim must save or reduce their dexterity by 1. If reduced to zero, their lungs turn to lava.

- Proboscis: After making her claw attacks, the Aasales can grab someone she hit and jab them with her sucking muzzle. Do however you do a grapple contest in your game, and if the Aasales wins she drains 1d4 HP from its target. An Aasales who has drained at least 5 HP in the past week is no longer slavering, and has a +1 to reactions and a -2 to morale.

- Parched: She swims through fire like water and water burns her like fire. Must test morale to attack a soaked person or cross over wet ground.

A ravenous cthonic predator. From the fiery forge that makes the world over and anew again, deep below the surface. She resembles nothing so much as a lioness or mountain cat, with a sharp, eversible needle-face and crunchy, chalky fur. Naturalists value her organs, as they are said to animate desiccated or mummified remains if sewn into them. Monks believe she is a metaphor for the fantasy covenant of their religion.