Osrynn's Oddments: Volcano Adventure - Super Hot Dungeon Adventure (for Level 4-6 Adventurers)

After making the Lava Rivers Battlemap a few weeks back, I realised how fun volcanic scenes were to create, as well as how many ideas I started to develop after posting (that I seriously regret not being able to include in the post). This adventure is my way of incorporating a whole bunch of these ideas and monsters, whilst also sharing a brand new adventure for this month!

When designing dungeons/adventures, there are a number of different styles that I’ve really wanted to work on, but find difficult with the sheer variety of playstyles available in 5e. You will notice that the majority of the adventures on the blog follow a linear path (begin in one place, follow a path, fight enemies, reach the end of the dungeon). This is the easiest type of dungeon to create for 5e, as it limits the players options for creative thinking, and leads to an adventure that can easily be run for any group.

The next type of dungeon design is multi-path dungeons; adventures where the party has to make a decision once (or multiple times), taking them down a different path. These usually lead to the same destination, and simply provide the players with a choice of the perils they will face on their journey (see my Cave of Two Paths adventure). These, again, are relatively simple to drop into any group, as the overall outcome of the adventure is the same, and the party simply have to make a few extra choices.

Finally, there are Central Room dungeons. These are the adventures where the party keeps on returning to a single room, for multiple different reasons. This can either because the paths they take away from the room lead them to trigger something that unlocks the next path, or because they find another way in, to allow themselves to progress down an otherwise inaccessible path. These can be difficult to integrate into 5e, as the characters can have such varied abilities, some of which may completely negate certain obstacles. A locked door is child's play to a rogue, or a caster with Knock prepared. A collapsed/missing bridge is great for stopping melee characters, but casters with Fly or Levitate can treat it as absolutely nothing. Because of these issues, creating a dungeon/adventure that relies on a central room mechanic is tough.

The Temple of the Elements was a simple example of how this can be integrated, through the four separate paths leading to the opening of a final doorway leading into the boss chamber, and hopefully, you will see this style represented in full for this new adventure.

The Quest

Through an acquaintance, the party learn of a local Wizard who is currently looking for a party of adventurers for a “small” job. Whether this Wizard is a local shopkeeper, a court wizard, a powerful ally, or anything else, I will leave up to you. When the party meet with the Wizard, they will explain that they need a group of adventurers to travel into an active volcano, and retrieve some Magma Gems. They will explain that these gems are worth a decent amount of gold, but also have strong magical properties. They will explain that they would go themselves, but they have a lot of research to do, and can’t leave their workstation right now.

They will ask the party to retrieve 3 Magma Gems from the deepest cave within the volcanic caves, and bring them back. In exchange, the party will be paid in gold (scale this to fit your campaign economy), as well as a favour (or whatever you want to give them, really, that’s up to you, I just write the adventures), as well as being able to keep any extra gems they may find (worth 100 gold per gem).

Lava Pools

This adventure is set inside an active volcano. As such, there is a lot of lava, and the whole area is very hot. If a character, for whatever reason, ends up entering a pool of lava, they take 8d6 fire damage. There is no save against taking this damage, and the character takes it for every round spent in/on the lava.

A character that is reduced to 0 hit points in the lava instantly takes this damage at the beginning of their turns, and it is counted as a failed death save. Any creature that dies as a result of being in the lava cannot have their body recovered, as it is considered destroyed.

Red Hot Floors

Certain areas of the map are extremely hot (noted in the area descriptions). These areas are not as bad as the lava pools, and any creature that enters it for the first time, or starts its turn there, must make a DC 14 Constitution Save, taking 1d4 fire damage on a failed save, or half as much on a success.

The Map

Labelled Version of the Map

V1 - Entrance Hall

The first cavern the party will find themselves in, V1 is an average sized cavern, with a raised path running between two separate exits, one to the southeast, leading out of the dungeon, and one to the northwest, leading to V2.

Either side of the pathway, there are small drops down (roughly 4-5 feet), to cracked volcanic ground. The party, upon entering the area, will notice the room to be extremely hot. If they decide to investigate (intelligence (investigation) check, DC 12), they will notice the heat coming from the lower areas, as well as from further into the cavern. These areas of ground are considered Red Hot Floors (mechanics above).

V2 - Central Room (First Visit)

The central area of the volcano, this large cavern actually has an open roof, and is clearly where the volcano would erupt from, should it be inclined to do so. The party will visit this area three times (at least) during their adventure, and as such, I will split up this area description into when they will visit each time.

The party will enter from the southeast of this cavern, and will find themselves immediately faced with a large pool of lava. After the sight, the next thing they will notice will be the heat; radiating off of the lava is a heat almost too hot for them to handle. To the north of them, there will be a path leading to another cavern, and over the pool they will see a few other small pathways, which lead into different areas, but are too far away for the party to reach.

The pathway leads the party to another exit to the cavern, leading them into V3, and across the lava pool they can see entrances into both V4, V5, and V6. The northernmost exit being entirely filled with lava, with no way to traverse it.

V3 - Torch Slime Cavern

At first glance, this room appears to be empty, other than a lava pool to the south of the chamber, winding round to the east. When they enter, the party will notice a faint sound echoing around the cavern. It will sound like a faint squelching noise, mixed with a sizzle. If they decide to investigate the room, they will find that (with an intelligence (investigation) or wisdom (perception) check, DC 14) there are 2d2 Torch Slimes (statblock below) clinging to the ceiling of the cavern, which is roughly 15 ft. high.

If the party decides to move in regardless, without checking, or without heeding them, the slimes will drop from the ceiling onto party members, attempting to make slam attacks against them. The slimes will be hostile towards any creature entering their cavern, except for the Lava Elemental (statblock below), which they are scared of, and will attempt to flee from.

The room itself is curved, leading between V2 and V4. The exit to the south west of the room leads straight into V2, onto the eastern pathway (see Central Room - First Visit). The northern exit leads to V4.

V4 - Balancing Act

The chamber V4 contains a large lava lake that takes up a good majority of the room. The path at the east side of the room, which leads in from V3, follows along the east wall, and about a third of a way along the north wall. When it stops, it is connected to a small island in the lake, by a thin stone walkway, which is in turn connected to a second island, and then to a walkway on the west side of the cavern by similar walkways.

To cross these walkways, a creature must pass a DC 14 dexterity (acrobatics) or strength (athletics) check. If they fail the check, they lose their footing, and slip off of the path. They do not fall immediately into the lava, however, and instead catch themselves awkwardly on the path. They take 1d6 bludgeoning damage, and 2d4 fire damage when this happens, but manage to pull themselves back upright, and onto the walkway and across. If they fail this check by 10 or more (rolling a 4 or lower), they instead fall into the lava, taking the damage as described above. If they fall in, they can be rescued with help from a party member, or by pulling themselves out (requiring an action).

They must make this check for each pathway they attempt to cross. Once a single party member has crossed, they can use the help action to aid others in crossing, allowing them to roll at advantage. Doing so, however, puts them at risk, and if the creature they are helping fails the check by 10 or more they are both pulled into the lava.

On the western side of the room, there is a second path, mirroring the path on the east side. Once the party reaches this, they can exit the cavern towards V5. The tunnel between the two areas is a curving path, roughly 5 ft. curving around slightly to the south.

V5 - Lava Weirds

The cavern they find themselves in contains 5 small pools of lava, each of which are connected underneath the floor of the cavern. Living inside the lava underneath the cavern are 2 Lava Weirds (statblock below), which will emerge from the pools to attack the first two creatures that come within 10 ft. of one of the pools. Due to each of the pools being connected, the lava weirds can move around underneath the surface of the cavern, to appear from any other pool.

These Lava Weirds will attack any living creature that enters the chamber, except for the Lava Elemental. They will choose to attack separate targets, if that is possible for them, and if no creatures are within range, they will opt to hide underneath the surface of the lava.

There are two exits to this chamber, one to the north, and one to the south. The northern exit leads the party to V4, and leads down a short 5 ft. wide tunnel. The southern exit leads the party back into V2 (see V2 - Second Visit), in the north west part of the room.

V2 - Central Room (Second Visit)

On their second time entering this room, the party will find themselves on the walkway opposite their original entrance. In the centre of the room, the lava pool seems to be bubbling angrily, and seems to occasionally shoot small spurts of lava into the air (not aimed towards any party members).

To the south, they can follow a short walkway, until they come to a small break. The break is filled with lava, and is 9 ft. across. A creature attempting to jump over this can do so if they have a strength score of 9 or higher, and they take a 10 ft. run up for their jump. A creature with a lower strength score cannot make the jump without assistance from another creature on the other side, using their help action to catch them and pull them up.

Once on the other side of this small break, the party will find the walkway to their south continues and eventually turns off to the west, into V6. As a creature turns the corner for V6, they will notice that the entire ground is covered in hot magma, and the floor from this point is considered Red Hot (as described above).

V6 - Ferrumolsk Den

Even from the entrance, the party will notice the creatures inside this cavern. Inside, 1d2+2 Ferrumolsk (statblock below) can be found. One of these will be completely blocking the tunnel exit leading west towards V7, and it will not move unless forced or attacked by the party. The other Ferrumolsk in this room will be suspicious of the party, but will not automatically attack. They will only become hostile if the party actively attacks one of them. If the party can succeed a DC 20 strength check, they can force the Ferrumolsk blocking their path to move by 10 ft.

For every round spent inside this area, the party must make their constitution saves as described in the Red Hot Floors section above. The room has two exits, one to the east, leading into V2, and one to the west, leading down a curved tunnel into V7. The Red Hot Floor continues down this corridor.

V7 - Magma Gem Room

After heading down the tunnel, the party will find themselves entering a larger cavern, largely taken up by two lava pools either side of a Red Hot walkway. At the end of the walkway they will see a small cluster of Magma Gems glistening in the cave wall. To remove one of these gems, a creature must succeed a DC 14 strength check, which can be made at advantage if they use a tool such as a chisel or pick.

Flying all around this room are tiny creatures. These Ember Flits (statblock below) are roughly three inches long, and are partially translucent. Their bodies resemble small winged tubes, with a pair of antennae at their head ends, and they seem content to simply fly around the room, occasionally dipping towards the lava pools to drink. If a creature comes within 5 ft. of one of these creatures, they will feel head radiating from its body, but will not take any damage. These creatures will not attack or even approach the party, opting to simply do their own thing. If, however, a party member attempts to harm or touch one of them, 3d2+2 Ember Flits will begin to attack any creature within their range.

If the party simply makes their way into this cavern, collects the gems, and leaves again, the Flits will not attack, but will become agitated, and begin to fly more erratically after any gems have been removed from the cavern wall. At the same time as this happens, the party will feel a small heat surge (not enough to deal damage, but the temperature will rise a little), and they will hear a faint rumbling from back in V2.

The party are able to harvest 2d3+2 Magma Gems from this cavern, before depleting the vein.

V2 - Central Room (Final Visit) - Lava Elemental Fight

Happy with their haul, the party will inevitably make their way out of the caves. To do so, however, they will have to pass back through V2 one more time. As they get closer to the central chamber, they will feel the heat growing more than before, as well as hearing the lava itself surging and bubbling more than ever before. When they enter, the lava will begin to grow in a large column in the centre of the pool, eventually forming a vague humanoid shape. This Lava Elemental (statblock below) will be immediately hostile towards the party, and will attack them on sight. It will focus attacks on whoever has had the most contact with the Magma Gems, and will especially try to kill whoever is carrying one or more of them. The Lava Elemental will take a Lair Action each round, on initiative count 20 (see below).

The party can subdue the elemental, should they wish, by throwing all Magma Gems harvested into the pool, which will cause the creature to submerge itself back underneath the surface, and stop being hostile. Otherwise, it will fight them until one side is dead. After the Lava Elemental is defeated, its body will begin to harden and crack into volcanic rocks, which will fall into the lava. When it is dead, all of the lava in the dungeon will begin to harden, becoming Red Hot Floors instead of Lava Pools, allowing the party to cross them with relative safety.

Lair Actions

On initiative count 20 (losing initiative ties), the Lava Elemental takes a lair action to cause one of the following effects; the Elemental can’t use the same effect two rounds in a row:

The guardian can summon 3 Fire Motes (statblock below), which will rise from the lava in any point within 25 ft. of the elementals body. These Motes are under the control of the Elemental, and are hostile towards the party.
The Elemental submerges itself briefly in the lava, granting it 2d8 temporary hit points.
The lava in the room begins to surge and bubble violently. The heat rising causes each creature inside V2 to make a DC 14 constitution saving throw, taking 2d6 fire damage on a failed save, or half as much on a success.