Silver Marches Sandbox 5 - S4 The Lost Caverns of Tsojcanth & Grimlight's Lair

North northeast of Sundabar on Mike Schley's map of the Silver Marches is a point-of-interest marked as Grimlight's Lair. Grimlight's Lair is described in the web enhancement for 3E's Silver Marches and it is revealed therein that Grimlight is a behir of gargantuan size.

Any time I see a behir mentioned I automatically think of the cover art by Erol Otus for the 1E adventures S4 Lost Caverns of Tsojcanth:

Linking the two together, I'm wondering whether Grimlight's Lair might be an appropriate location to place an adapted/updated version of S4 The Lost Caverns of Tsojcanth with Grimlight the behir acting as a rather dangerous guardian of the entrance. Lost Caverns is fairly Greyhawk-intensive in terms of its backstory, but I think the location itself can be quite easily adapted to the Forgotten Realms as most of the backstory is largely irrelevant in the context of actually playing the adventure.

A Revised Background

During the Netherese era, the archmage Tsojcanth (for the moment at least, Tsojcanth is now a Netherese archmage... or is he?) explored the wilderlands north and west of Netheril seeking places of ancient, primordial magic. The region now known as the Cold Vale is a dangerous place of sudden deep gorges, many of which serve as lairs for trolls, leucrotta and worse. Among these gorges Tsojcanth found a ravine carved by a river, although the river has long since diminished and split into many smaller streams.

 

One of those streams still winds through the ravine, although it alternates between two different beds every few years. The walls of the gorge are fairly rough and climb steeply from the ravine’s floor to a height of 50 feet (the level of the surrounding land). The stream, which measures never more than about 2 feet deep, runs from the southwestern end of the ravine to the northeastern end. After another hundred feet it empties into a small pond, which drains through the rock into the Underdark.
 

The middle of the ravine has a hill, part of which has been hollowed out to form a small cave. That cave is now the lair of the legendary behir Grimlight but, more importantly, serves as the entrance to a series of caverns discovered by Tsojcanth that echo with powerful magic even in these years after the Spellplague.

 

What Tsojcanth discovered was a planar nexus that linked several different planes but was also, in some ways, outside of normal space and time. These properties made the caverns an excellent place to perform arcane experiments and also to hide powerful items as no divination magic - not even that possessed by a deity - was sufficient to penetrate the weirdness of this place. It also allowed Tsojcanth to walk between many worlds and ultimately he departed Toril after Karsus's Folly believing that magic in Toril was now dead.

With this sort of background, I suppose I can justify almost any encounter and almost any sort of final treasure. It's a lot less detailed than the background provided by Lost Caverns but I think it's sufficient for the purposes of a sandbox campaign, particularly one that isn't even set in Greyhawk!

The background also suggests that the Netherese that I have mentioned in my other posts in this series are likely to be involved. In fact, pursuing the Netherese might be the most appropriate hook for the PCs to follow. Alternatively, one of the Morueme family of blue dragon wizards from the eastern Nether Mountains might be involved or exploring the Lost Caverns could simply be a mission the PCs perform on behalf of someone powerful (and official) in Silverymoon.

Wilderness Encounters

The wilderness section of the original Lost Caverns was actually a fairly important part of the adventure, and it also tied in to the wilderness section of the "sister" adventure to Lost Caverns, WG4 The Forgotten Temple of Tharizdun (which is yet another 1E adventure I would like to adapt for this campaign).

Grimlight's Lair is set in different terrain - and on a different world! - to the original Lost Caverns so a lot of the encounters won't make sense but they can still inspire some encounters that are more appropriate to this campaign:

 

Barbarians

 

Uthgardt barbarians may be potential allies or little better than brigands depending on their tribe and/or inclination.

Border Patrol

Dwarves and humans from Citadel Adbar patrol this region in other to keep the trade roads between Adbar and Citadel Felbarr as well as Silverymoon free of bandits, barbarians, goblins, orcs and other creatures. These sorts of patrols should be fairly common.

The Craggy Dells

(This is essentially lifted whole cloth from Lost Caverns.)

This isolated place is one of rugged beauty, with rock spires and jutting mesas rising from a dish-shaped valley. The rock formations make the place a series of meadows and dells. There are scattered shrubs and a few copses of trees, but most of the area is covered with lush grasses. Game is common amidst the dells of the valley.

The towering peaks serve as home to a herd of hippogriffs. This group consists of a male and his harem. There are eight nests with a total of three fledglings in one pair of nests and four eggs in two others. This flock nests at the far southeastern edge of the valley.

A group of renegade humans and orcs, led by a particularly vile half-orc assassin, is currently camped in the Craggy Dells. They are capturing hippogriffs and fledglings to sell them later to certain powerful individuals (Netherese? Zhentarim?) who have promised to pay well for the creatures.

The Hermit

It wouldn't be a Gary Gygax-inspired adventure without a strange hermit. Perhaps this is some sort of spellscarred seer dwelling in his own personal plagueland, or perhaps a lonely druid who sees himself as the self-appointed protector of the Cold Vale.

Hobgoblin War Party

Led by a cunning warchief, this war party of hobgoblins is en route to destroy a band of orcs that have moved into territory claimed by the hobgoblins. And while I haven't given any thought to which tribe it might be, my plan for this campaign is to make sure any bugbear, goblin, hobgoblin and/or orc encountered belongs to a tribe and for the tribal affiliation to be reflected in the creature's appearance and, ideally, in its stat block.

Ogre Den

These ogres are unusual in that they are mercenaries for competing orc tribes taking the pay of one tribe each war season. They are surprisingly cunning in battle but that is because their leader is actually an ogre mage.

Troll Cave

This location should be given away by its stench. A hideous she-troll, possibly a cleric of Vaprak, leads a band of trolls who frequently menace travellers through the Cold Vale. There may be a significant reward for slaying these trolls on offer from the authories in Citadel Adbar and/or Citadel Felbarr as a result.

Wyvern Roost

A mated pair of wyverns with a clutch of three eggs hunts for meat to feed their soon-to-hatch offspring. If one of the wyverns is slain, the other will enter a berserk fury.

Hill Giants

The campaign is probably at a level by this point where encounters with hill giants (level 8 brutes IMC) are level-appropriate. They are hunters and raiders from the Rauvin Mountains.

Lesser Caverns

Lesser Caverns (Upper Level) of the Lost Caverns of Tsojcanth

The planar nexus nature of this location suggests that there is a lot of "leakage" from other planes. I can imagine that Far Realms creatures, in particular, would be attracted to this so I am thinking that aboleth would be a perfect fit for the Lesser Caverns, especially with there being so much water present.

I'm not sure how many encounters from the original I would keep but I do like the idea that there is a marid (water genie) imprisoned in area 22 who can be freed. That seems to be an appropriate reward for a party prepared to brave the dangers of the water... especially considering my plan to use aboleth.

Greater Caverns

Greater Caverns (Lower Level) of the Lost Caverns of Tsojcanth

The real attraction of this adventure is that the final treasure in area 20 can only be accessed once the puzzle of the teleporting doors is solved. While I am not sure yet what the final treasure will be, I do know that I definitely want to keep the teleporting doors.

I'm also thinking that this level should have a strong abyssal theme. The breakdown in time and space attracted aboleth and their servitors to the Lesser Caverns; here it has attracted fiends from the Abyss. Another reason for this is that I am also wondering about having the Staff of Fraz-Urb'luu hidden in area 20 and its presence, though hidden from Fraz et al, is still potent enough to lure abyssal creatures to this place.

 

But really this is just a place to kill things and take their stuff. I think if I am going to run Lost Caverns, even in an updated form, it's probably best to simply keep that old school feel and leave high fantasy plots to another campaign.