Once a mere shadowbeast, the Swollen Shadow has ascended beyond it's brethren. It has taken possession of a spellsphere formerly used to power one of the Shining Towers, subverting the arcane battery into a wellspring of power that fuels a monstrous increase in size. Now it stalks the city of Shardis, thirsting for flesh and blood.
The Swollen Shadow retains the three special abilities that a normal shadowbeast has (modified slightly), yet it also has one that is uniquely it's own.
Shadow Tendrils: As with a normal shadowbeast, these can be used to bludgeon, grab, drag, trip, squeeze, etc. Unlike it's brethren, the Swollen Shadow can manifest any number of tendrils, each capable of independent action; however, it only has the concentration to actively manage 3 of them at any one time. The rest just remain in stand-by until "reactivated". A character grabbed by a tendril can more easily escape if that tendril is not actively being managed by the over-sized shadowbeast.
Blistering Shadows: As normal, though the larger size and more numerous tendrils make this more dangerous.
Quaking Fear: As normal.
Engulfing Darkness: Thanks to the spellsphere that fuels it's massive growth, the Swollen Shadow can easily surround someone with it's very body, rending and tearing them apart as their flesh melts and dissolves. Unlike a normal shadowbeast, the Swollen Shadow is large enough that escape cannot be attained through struggle; the target is entirely covered, and must fight their way free through the body of the beast.
The Swollen Shadow, while much larger than it's standard-sized kin, still retains the same mindset. It prefers sneak-attacks, and given the chance will wait until escape is impossible. It will attempt to pick off stragglers in groups, dragging them away to be torn apart and eaten. If it thinks it can get away with it, it will engulf an entire group at once and try to consume them all, like a macabre all-you-can-eat buffet. It also requires a much stronger source of light to ward off than it's smaller relatives.
Defeating the Swollen Shadow is a difficult task. There are three main ways to do so:
- Massive magical damage. Even with the power of the spellsphere backing it, enough magical damage will force the shadowbeast into retreat to regenerate it's wounds.
- Intense quantities of light. While more resistant to light than it's fellow denizens, the Swollen Shadow isn't immune to the purifying power of illumination, and enough will kill it.
- Remove the spellsphere. While difficult (the PCs must first figure out that it's the source of the Shadow's power, and then figure out a way to remove it), doing this will cause the Swollen Shadow to revert back to a normal shadowbeast, which can be removed with a much smaller application of force.
These aren't the only ways to defeat or kill the beast, merely the most obvious ones. Creativity should be rewarded appropriately.
This isn't intended to be a one-off encounter with a disposable monster. The Swollen Shadow should be a difficult fight, and most parties should find it nearly impossible to defeat it conventionally, i.e. hack-n-slash. Discretion is the better part of valor, and it should become quickly apparent that the best course of action for the PCs is to run.
This shift in focus also allows the GM to make the Swollen Shadow a recurring encounter that the PCs must constantly try to avoid as they roam the city streets. Knowing that it's out there, looking for them, and that they can't just blast it with fireballs until it dies will ratchet up the tension significantly. Add on chase scenes, and a few half-encounters where they have to hold it off for just a few moments until they can escape, and you've got the makings of a truly epic session.
Of course, the PCs should eventually be able to defeat it, as detailed above. But in a city shrouded in darkness, where will the average party get the amount of light that they need to bring it down permanently, and how can the GM give them the idea without hitting them over the head with it?
The former can be solved by the sole remaining Shining Tower, which provides a haven from even the harshest of hellish invaders. If the PCs can somehow concentrate the light from one of the Towers onto the Swollen Shadow, it will pop like an overripe balloon. A sneakier way of handling this would be to lure the beast into one of the disabled towers and somehow turn it back on. One Tower doesn't have a power source (its spellsphere is powering the Swollen Shadow, remember), and the other has suffered damage and must be repaired before it can be used, so either option presents difficulties. Both should be viable options, however.
As for leading the PCs to the idea of overwhelming the Shadow will lots of light, the best method is to drop clues. One standard rule of thumb is 3 clues for anything you want to PCs to figure out or go to, so 3 ready-made clues are provided below. Use or ignore as you see fit.
Clue #1: The Shining Towers
The use of the Shining Towers as refugee points after the Eclipse should clue the PCs in on the distaste the monsters have for light (if they haven't already figured it out). If they ask an NPC, they can quickly get an answer to the effect of, "Them creatures don't seem to like the light. Seems t' hurt'em."
Clue #2: Overheard NPCs
Slightly more obvious, but you can have the PCs overhear a pair of NPCs arguing about whether the light from the Shining Towers would actually kill off the monsters, or whether it would just drive them away.
Clue #3: Practical Magic
Let the PCs see first-hand a group of guardsmen lure a normal shadowbeast out into the open, then kill it with a large flare of light from a spell. This is the most obvious way to let them know how to handle the threat, but also the most effective. With this, they've seen it work directly, and should recognize that it'll work on the larger Swollen Shadow if they can get enough light.