Underdark adventure with Demons, Beholders, Elementals and a Hydra


This post complies and adds to some actual play examples I've been giving in recent New Horizons threads. It is long.

By misadventure, the PCs in my game have ended up in the Underdark. They are looking for the Soul Abbatoir, using a magical tapestry woven in an ancient minotaur kingdom as their map.

Although this is the PCs ultimate goal, they actually entered the Underdark before they had really planned to - two PCs, following a trail left by Orcus cultists they had beaten up in an earlier session, headed down a long flight of stairs deep into the earth and stumbled upon an ancient underground temple to Orcus.

At the same time, the other half of the party was fighting a sphinx in a hidden temple that they had teleported into by reversing an NPC Leomund's Secret Chest. But just as those PCs were about to beat the sphinx they got teleported into the Orcus temple instead, in order to save their friends who had ended up in a fight somewhat out of their depth. (The teleportation was performed by the PC invoker using Astral Step, but enhanced by the sphinx - it conjured a vision of the PCs' friends being beaten up in the Orcus temple, and then happily let the PCs teleport into that scene in order to save itself from them!)

As GM, it hadn't occurred to me to place an Orcus temple until one of the players said that his PC spent time going around town trying to find out where the cultists had come from and what they were up to. But I found a suitable poster map in Death's Reach (the one with the statues, pillars and altar) and had some monsters statted up - immoliths and other demons.

After clearing out the demons and dealing with the Altar of Zealotry in the temple (that had fun dominating the dwarf fighter), the PCs opened the back door behind the altar and could see Moria-like stairs descending further into the depths (the map is from one of the 4e Dungeon adventures, Siege of Bordrin's Watch). As they were checking out the stairs they were attacked by a nightwalker and its bodak servants. The idea of putting the stairs there, and using a nightwalker as a balrog substitute, was something I came up with in the time between sessions. But it was easy to narrate a weakening of the barrier between world and Shadowfell in the vicinity of an ancient Orcus temple. This encounter was quite a bit of fun, as a couple of PCs got knocked off the stairs (but, being 17th level, survived), and I got to use the bodaks' Death Gaze successfully at least once (maybe twice) and also Finger of Death from the nightwalker.

Once the PCs had beaten the nightwalker and bodaks, and were searching around, one of them tried to sense if there was any more shadow energy leeching through. I said that there was, and expected the PCs to try to seal the breach. But instead they took up positions and prepared for combat - so I had a dracolich attended by lost souls (levelled-up wraith figments) come through the barrier. This was another interesting combat - I used the MV rather than the MM dracolich, which included more domination of the fighter - and I got to reuse my poster map!

The PCs then conjured a Hallowed Temple (via ritual) in order to take an extended rest. They commenced the next day still at 17th level, but since then they have completed six encounters and are now 18th level.

After resting in their temple they went down the stairs. I had just got my copy of Into the Unknown, and used a picture in it, of an underdark staircase in a vast cavern, to indicate the general character of their descent. I had statted up some 22nd level death giants as part of general prep, expecting that they might come in handy, and used them - plus an eidolon, levelled up to 17th - to ad lib an encounter (18th level overall) at the bottom of the stairs involving a locked door, and the guardians on the other side of it protecting the sealing away of this ancient Orcus temple complex. I decided that the giants had been placed there by the Raven Queen, under a geas to serve as warders against the servants of Orcus; the eidolon had been created by the Raven Queen and Torog.

I thought the PCs might try to negotiate, and they did, but the dwarf fighter wields a giant-hating dwarven thrower artefact, and the paladin of the Raven Queen is pretty rabid too, so the idea of negotiating peaceful passage in return for lifting the geas on the giants didn't get very far. Combat ensued, although the paladin managed to ensure that only one of the giants was actually killed (the other was knocked out, and will regain consciousness still geased). This encounter also involved the invoker spending a healing surge for a Knock ritual to open the sealed door. On the whole, an easy encounter.

As the PCs continue through the tunnels, I described them coming to a cleft in the floor, and got them to describe how they would cross it. The drow sorcerer indicated that he would first fly over (using 16th level At Will Dominant Winds) and then . . . before he could finish, I launched into my beholder encounter, which I had designed inspired by this image (which is the cover art from Dungeonscape, I think):



I'm not sure exactly what the artist intended, but to me it looks as if the central beholder is hovering over a chasm, with uneven rocky surfaces leading up to it (archer on one side, flaming sword guy on the other). I drew up my map similiarly, including with the side tunnel (behind the tiefling) which on my version ran down into the chasm, and the columns, stalactites, etc.

I didn't use four beholders, only 2 - an eye tyrant (MV version) and an eye of flame advanced to 17th level and MM3-ed for damage. And also a 15th level roper from MV, introduced on a whim when the player of the wizard asked, before taking cover behind a column, if it looked suspicious. (Response to result of 28 on the Perception check before adding the +2 bonus for knowing what he is looking for - "Yes, yes it does!")

Anyway, the terrain was pretty awesome, though hugely punishing for the PCs. I managed to get both ranged strikers down the 200' drop into the stream below early in the encounter - the drow sorcerer made it back up (Dominant Winds again, using his Acrobatics to land on ledges on the cliff at the end of each movement) but the ranger-cleric, after getting about 120' back up on his flying carpet, got knocked back down to the bottom. He still ended up being pretty effective, though, shooting up at long range with Twin Strike.

I failed in my attempt (as an eye tyrant) to use my TK ray to impale the dwarf fighter on a stalactite, and then the PC invoker did that to me instead - twice - using a slide effect from his zone of darkness and cold (Shadowdark Invocation; I resolved the stalactite as 2d8+8 and immoblised (SE), which seemed OK for a 17th level situational but multi-use option). But I did get to petrify one PC (the drow sorcerer) and at one stage had 3 or even 4 PCs taking ongoing 2d20 from my disintegrate ray (paladin, fighter, sorcerer and invoker - all very close together, but maybe only 3 overlapped at once).

Besides reinforcing my fondness for the tactical mobility that 4e generates, it also taught me that 4e beholders are pretty brutal (and play more like control than artillery - especially in combination with the terrain, a lot of action denial). The player of the fighter, in particular, got rather hosed in the fight - moving in close, and therefore vulnerable to the central eye, which is a vs Will attack that limits attacks to At Wills (his Will is not terrible, but his AC and Fort are both better). Which meant he didn't get to use some of his more funky immediate actions, and took a long time, and some effective use of cover while the beholder was trapped in the zone, to get off his close burst that also triggers AoE healing and thereby kept both himself and the invoker in the fight.

This was a level 21 encounter overall, and got the PCs up to 18th.

The PCs had two ways out - the main tunnel, and the side tunnel that the eye of flame had come out of - and decided to go down the latter, as (i) it went down (and they think they want to go down to find the Abbatoir) and (ii) it seemed warm, and for some reason that I now can't remember that appealed to them. There were three minor encounters - a single fungal hazard dealt with by the ranger while expanding an overgrown, abandoned duergar farm, and a couple of skill challenges. The first, which had been commenced back at 17th level and involved navigating through the underdark, failed, and the PC fighter ended up falling through thin stone into the underground river the duergar had relied upon to irrigate their fungi. This then triggered another skill challenge for the party to recover the fighter and regroup successfully in the river, and they succeeded at that.

The regrouping in the underground river had involved the invoker summoning Phantom Steeds, and for a couple of reasons they proceeded downstream, all mounted up. The first reason was that the invoker - whose Sceptre of Erathis (= the Rod of 7 Parts) had already hinted that other pieces of it might be near - felt a very strong urge to head downriver. The second was that the very Bluff-y drow backed him up - I can't remember what the ostensible reason was, though it will have been backed up by a 30+ Bluff result, but the real reason was that he could sense chaotic, elemental power downstream, and he is a a chaos sorcerer who revels in imbuing himself with chaotic energy.

After heading down this underground river for some time, they came onto their sixth encounter of the day. This started as a 21st level enounter - an 18th solo hydra (a flamekiss hydra spawned from the primordial Bryakus) and 3 16th level salamander guards, one of them elite.

Before explaining how this unfolded, however, I need to describe the terrain. The encounter occurred at the point at which the underground river down which the PCs were travelling meets a lava pool. This confluence of elements has led to five distinct terrain "zones":

*The ledge on the non-lave side of the river: safe terrain (if you can fly/climb/teleport up to it), but with lightly obscuring steam between it and the rest of the cavern.

*The river, heated by the lava, that inflicts 10 fire damage when you enter or start your turn in it, and carries you 2 squares downstream.

*The cooled lava adjacent to the river, that is difficult terrain and inflicts 10 fire damage when you enter or start you turn on it. This is where the hydra was.

*The lava itself, that is difficult terrain, inflicts 20 fire damage, plus prone and dazed, when you enter it, plus 20 ongong fire damage and dazed (save ends once you get off the lava), plus a DC 17 End check to avoid falling prone if you start your turn on it. If you are adjacent to it, you take 10 fire damage at the start of your turn.

*The solid (higher melting point) rock beyond the lava. This is safe in itself, but is where the salamanders were.

*Finally, throughout the cavern except (i) on the safe ledge on the far side of the river, and (ii) in one part of the cavern which has a natural vent in its ceiling, there are fumes coming off the lava that require a DC 17 End check at the start of the turn: failure inflicts 5 poison damage, plus Slowed until the end of your turn.​

The encounter began with the heated water destroying the Phantom Steeds at the start of each PCs' turn. The drow flew up to the river ledge, and flew the invoker up likewise, who then teleported the ranger (and maybe fighter?) up. The salamanders "jumped" across the lava (they don't have legs, but are quite big, and I envisaged them using muscular contraction like a snake) to join the hydra, and opened up negotiations "Are you emissaries?" they asked in Primordial. The Bluff-y drow, who speaks Primordial using a Polyglot Gem that he created in an earlier session by imbuing it with the essence of his Air Mephit familiar, spouted some nonsense in reply, and generally kept the salamanders from launching an attack (and they also dissuaded the clearly angry hydra from going at it) while the paladin (a tiefling, so not minding the heat) swam to the cooling lava (using his Shield of Floating as a surfboard). Once the paladin was in position, he engaged the hydra. The invoker (who is a multi-class wizard) meanwhile opened up an Arcane Gate, and the fighter stepped through it (I think - he may also have been swimming, though) and joined the paladin in melee.

(I think this fight had more relevant resistances than any other I've GMed: as well as the tiefling, and obviously all my monsters with their fire resistance, the drow sorcerer had already set his variable resistance to poison (when checking out the fungi), and used fire resistance from his Demonskin Tatoo to reduce the fire damage. The invoker has a Book Imp familiar that gives him some fire resistance too. The dwarf fighter was somewhat punished by the heat, however.)

Anyway, this melee was brutal. The PCs, in the first three or so rounds of combat, delivered about 500 points of damage to the hydra, and took out one of its three salamander guards and bloodied the other two on the way there. Those 500 points were enough to take out two of the hydra's four heads, and at each point the PCs were able to use cold damage (Enfeebling Strike in combination with the Winter Domain feat, and a +1 Frost Arrow that had been retained from quite a lower level) to stop it growing two new heads in lieu. And salamanders were pushed into the lava, and while they have fire resistance they still suffered the conditions - pretty brutal action denial! (The hydra, which has some forced movement from its fire breath, was getting some push too, but into the river rather than the lava.)

But just as the PCs were getting pretty cocky, the hydra managed to finally shake off the various dazing, blinding and other action denial/debuff affects they had placed on it (I used a combination of the MM and MV Many-headed traits, and applied them to blindness also, to give my hydra a chance against my action-denying party), and it was able to spend an action point on its turn for useful effect, getting 6 attacks against the fighter (two times two heads on each standard action, plus two free attacks at the end of the fighter's turn) - four bites for 4d10+10 (critting with one of those for 50 points from that bite alone) and two fire breaths for a bit less than that. And it dropped the fighter from 105 to -62 (just above negative bloodied) with those attacks. (There was also about 30 points of damage from the various environmental effects and ongoing fire damage inflicted by one of the bites.)

The fact that the fighter had half-a-dozen surges left with a surge value of 40 or so each didn't help him!

The invoker was able to slide the fighter out through the Arcane Gate, but that left the paladin alone in melee. And one of the salamanders had called for reinforcements, whom the PCs could see now arriving - two 17th level salamander archers, and 4 archons of 17th and 18th level, taking the level of the whole encounter up to 23rd.

At that point the session had to end mid-fight: the photo of the battlemap is attached below. We took it up two weeks later. I wasn't sure what the PCs would do - the paladin, with better AC than the fighter (plate rather than scale, heavy shield, and meliorating armour one milestone into the day), probably had a better chance in melee, but the hydra still has one action point unexpended! For a party low on surges and dailies after the punishing fight with the beholders, I though they might decide that it is a bit too much, and try to retreat downriver.

Anyway, as is their usual habit they planned tactics via email for 2 weeks (without copying me in - I only get copied into the rules queries and the organisation of time and location for the next session!). And we reconvened for the epic battle.

Their planning was "Dunkirk and then Normandy" - the paladin fell back through the Arcane Gate, so the whole party was on the safe side of the river, and the fighter was brought back to consciousness. But the player of the invoker was worried about the salamander archers - he and the sorcerer are limited to range 10 attacks, and he didn't think the PC ranger could handle a long-range archery duel against the two on his own. So he unilaterally reconfigure the "Normandy" part of the plan: he permanently expended his Ritual Candle in order to shift the location of his already-cast Arcane Gate to another point within range, namely on the "safe" rock on the far side of the lava pool, so that the PCs could go through and lock down the salamander archers in melee. (Success was adjudicated using an Arcana check; the fictional logic was that the character sucked all the power out of the candle in order to use his knowledge of the Linked Portal ritual to close and reopen his Arcane Gate.)

The PCs also planned to use their Fire Horn to strip all the enemies' fire resistance off, and then have a bit of a lava-fest!

But it all somehow went a bit wrong. The archons turned out to be tougher than expected, and the dwarf fighter found himself flanked, cut down, and had to be sent back through the Arcane Gate a second time. He was brought back to consciousness, but spent the rest of the fight on the far side of the river - though not to no avail, as he distracted the hydra and drew the bulk of its attacks (range 10 fire breaths).

Meanwhile, the ranger-cleric came through the Gate, and used the Fire Horn, and then Mantle of Glory (? a clerical push power) to get some lava action going. But this meant he had stopped Twin Striking the hydra (which by now had dropped to one quarter hit points, but had grown two more heads for three in total, because the sorcerer had missed when he tried to stop the regrowth with an acid orb).

The invoker-wizard also came through the gate, in order to Thunderwave some elementals into the lava, but this turned out to expose him to their vicious melee and he, too, got cut down. In desperate straits as he lay on the ground next to his Gate (he was brought back to consciousness via some sort of healing effect), being hacked down by fire archons, he spoke a prayer to Erathis (one of his patron deities). After speaking the prayer, and after the player succeeded at a Hard Religion check, as the PC looked up into the rock cleft high above him, he saw a duergar standing on a ledge looking down. The PC already knew that the duergar revere Erathis (as well as Asmodeus). The duergar gave the Deep Speech hand sign for "I will offer you aid", and the PC replied with the sign for "The dues will be paid". The duergar then dropped a potion vial down to the PC. (I had already decided that I could place a duergar in the cleft if I wanted some sort of 3rd-party intervention into the fight. The successful prayer was the trigger for implementing that prior decision.)

The invoker took himself and his potion back through the Gate, and he too stayed on the far side of the river for the rest of the fight.

The ranger-cleric, with no clerical powers left, pulled out of his Carpet of Flying and took to the air, to take down the hydra and then the elementals via archery.

And the sorcerer, cut off from the other PCs by a pack of archons and salamanders and a pool of lava, practically down to At-Will powers, and low on hit points, called upon the ambient chaotic energies of all those elemental monsters. After an Arcana check good enough to succeed at a Hard level 12 DC, he mustered enough chaotic energy to give himself 12 temporary hit points - but it also activiated the sigils of the Queen of Chaos that are permanently emblazoned on the insides of his eyelids (he is a Demonskin Adept), blinding him, and it had the same effect on his Robe of Eyes, so he couldn't see!

One archon stepped through the Arcane Gate and took up the fight on the other side of the river. It cut down the invoker (again!) but was ultimately beaten in melee by the dwarf fighter and the paladin. The fighter, at some point, got knocked unconscious again (either by the hydra or the archon, I can't remember) but was brought up with a 1st level healing potion (from Mordenkainen's Magnificent Emporium) and saw out the rest of the melee vs the archon on single digit hit points.

Meanwhile, the blinded sorcerer tried to escape down a tunnel at the other end of the cavern as the remaining archons and salamanders focused on the other PCs, but eventually, having no one else to take on, they turned back to him, pursued him and (in the end) knocked him unconscious. The carpet-borne ranger came to his rescue, and so did the paladin - diving into the river, swimming back across on his shield, running over the cooling lava, as he ran past the body of the now-dead hydra picking up the shard of the Sceptre of Erathis that had been embedded in its neck, jumping the lava and falling just short (taking a bit of damage despite his resistance, and a lot of action denial), and then getting into melee.

Two archon ash dicsiples and four remaining salamanders (a lancer, an elite firetail and two archers) were killed, but it turned into a standoff - the last standing archon took the unconscious sorcerer hostage with his scimitar to his throat, while the ranger-cleric sat on his carpet with bow drawn and aimed, and the paladin entered into negotiations, picking up the Polyglot Gem that the archon had thrown to the ground for this purpose.

The archon offered the sorcerer's life in exchange for the shard taken from the neck of the Spawn of Bryakus. The paladin stalled for a bit, and then teleported next to the archon with an unexpected Winter's Arrival (a rare event in the lair of the fire elementals!) and tried to interpose himself between scimitar and throat, but was not quick enough and the sorcerer's throat was cut (fatal coup de grace against the unconscious PC).

The paladin wondered what he could do to help his friend. Removing his Diamond Cincture, he tried to imbue its healing energy into the sorcerer. With a successful Medium Healing check by his player, and channelling his own life force through it, he brought the sorcerer back to life (but still unconscious). But the paladin himself fell into unconsciousness, drained of his own life energy, and the diamond is not going to regain its lustre after anyone's Extended Rest - it is permanently drained. (A Diamond Cincture, at 10th level, actually has the same value as the components for a paragon Raise Dead, which made this particularly easy to adjudicate.)

At the same time, the ranger let loose a volley of arrows, but the archon, after taking a last (but non-fatal) cut against the unconscious sorcerer, grabbed the shard from the paladin's unconcsious body and ran off down the tunnel. The ranger dropped the 70' from his carpet (taking no damage, due to his Acrobatis and his Safewing Amulet) and set off in pursuit. He was able to take two shots at long range against the fleeing archon, and one arrow struck true, killing the elemental. He then returned to his two companions and administered potions of healing to revive them. All three are now crouching low on the floor of the cave, below where the fumes pool (ie no Endurance checks required).

The fighter and invoker, meanwhile, remain on the ledge on the far side of the river, while the shard of the sceptre lies where the archon fell.

So the PCs were victorious, but only just. At the point where the fighter and wizard went back to the ledge, the general mood was of impending TPK, but there is nothing like a flying ranger to turn the tide! The party has pulled off some pretty surprising victories before (eg against Calastryx), but this was probably the most epic yet.

They are now hoping to create a Hallowed Temple and take an extended rest, but (unbeknownst to them) will have to deal with the duergar first. After all, the invoker promised that the dues would be repaid!


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Great stuff and I'm sure considerable fun for all.

You've mentioned Claremont's run on X-Men as an inspiration for your mood/tone/pace. I'm curious. Would you say that your 4e game maps to a D&D high fantasy version of Claremont's X-Men or do you have another take on it. If so, do you draw from any specific issues or story arcs specifically? Any of the above specifically derived from panels or story arcs? I used to be a pretty big comic book nerd so I'm very familiar with the source material.



I haven't drawn on any particular panels or story arcs, at least not consciously.

For me, the influence of the X-Men works in a few ways, primarily about method/structure rather than detailed content:

* The X-Men features a lot of physical conflict, but it is not about combat. Fisticuffs is a means of representing confict within the contraints of the 4-colour genre tropes. (The Hulk is another example - it's about the struggle betweeen Id (the Hulk), the Ego (Thunderbolt Ross) and the Super-ego (Banner), with Doc Samson as the analyst - but it uses physical conflict as its medium. I enjoy the Hulk more than a lot of other literary or academic treatments of Freud!)

* The X-Men involves a party. So it shows arcs and antagonists that establish links between superficially disparate protagonists. I think this is quite an important technique for making D&D work nicely when genre and theme are important to play. You don't want it to look completely arbitrary that the PCs have a longstanding, coopeative relationship.

* The X-Men involves long-running, complex, overlapping story arcs. Which, I think, D&D also benefits from (if you're going to keep the game going from 1st up to epic).

* The X-Men is about a special group of individuals - the mutants - who are somewhat outside of, and in sheer power terms superior to, ordinary society. And it gives a model of how to establish at least a fig-leaf of plausibility for the existence of that group, and its various factions and cabals, within ordinary society. In D&D, this is the problem of "Why don't the PCs, or their antagonists, just conquer the world?" I'm not saying the X-Men provides an answer to that question, but it provides an example of world flavour that can help discourage the question from being asked.​

In the sort of game I run, the PCs really are more like a superhero team than like the mercenary band that Gygax and Arneson may have had in mind when they first started running the game. And the open-ended campaign is more like an ongoing comic series than a movie or novel. So I think there's a certain logic in drawing on that material. And in my personal view Claremont X-Men is some of the best! (Despite the somewhat ignomious ending to it.)

Good use of suitably interesting terrain and effects. This helps to show the WHY 4e style combat/action is cool. I'd get a little more dynamic and a little more tight between plot and action if I were using this as a model example of the best you can do with 4e, but I'm sure it was plenty fun to play.


That's an excellent post and very thought-provoking. I have always considered myself inspired primarily by Dean Koontz's pacing conventions and a genre amalgamation of the Dark Tower series, Star Wars, LotR, The Princess Bride and the A-Team (varying depending upon the campaign/story arc). Its funny but before your initial invocation of Claremont's X-Men, I had (ashamedly as I pride myself on being thoughtful) never considered comic books' influence on me (even though I grew up entrenched in the medium). I suspect that there is more Claremont's X-Men (for the reasons you elaborated upon) in my pacing and genre preferences than I initially envisioned.


I'd get a little more dynamic and a little more tight between plot and action if I were using this as a model example of the best you can do with 4e
Fair comment.

The beholder encounter was primarily colour - a dynamic picture, plus a mechanically interesting monster, that I wanted to bring into the game.

The hydra encounter was thematically richer, though, and I've tried to bring that out in the post above. The trigger for the encounter was the respective urgings of law and chaos, and this recurred in the contrast between the wild hydra and its organised guards, the PCs oscillating between order and fiasco, and the "page 42" events like the prayer, the intervention of the duergar, the invocation of chaotic forces, the negotiation over the shard of the Sceptre of Erathis, etc.

Does that help?

Fair comment.

The beholder encounter was primarily colour - a dynamic picture, plus a mechanically interesting monster, that I wanted to bring into the game.

The hydra encounter was thematically richer, though, and I've tried to bring that out in the post above. The trigger for the encounter was the respective urgings of law and chaos, and this recurred in the contrast between the wild hydra and its organised guards, the PCs oscillating between order and fiasco, and the "page 42" events like the prayer, the intervention of the duergar, the invocation of chaotic forces, the negotiation over the shard of the Sceptre of Erathis, etc.

Does that help?
I think they were all GOOD, and definitely beyond any basic criticism. I think yes, for purposes of being nearly perfect, the Hydra encounter has definitely a little bit more of that sort of "there's more going on there than a fight" thing. OTOH you have a pretty strong plot throughout the adventure overall, and I think beholders are just too damn cool, so overall I'd sign up! ;)

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