Trolls in Duscuro
Trolls are of elemental ancestry. Their bodies are stony flesh and their blood is filthy mud. The earth is their mother, and she has made them strong.
Every troll forms a bond with a stone, whether it is a stony hill, a mesa, or a cavern. Many trolls seek out stone ruins or abandoned forts, and bond themselves to that structure. While they live, the fort still stands. And while the fort still stands, they live.
Aside from that, you've seen these trolls before. They are huge, muscular humanoids with squashed faces, jagged teeth, and hands the size of a dinner table. They eat people, and stalk through wild places. Sunlight turns them to stone, but burial revives them in four days. They regenerate any injury, even missing limbs. They fear fire, which reminds them of their enemy, the sun. Their great regeneration is halted by burns and acid.
The city of Diamako is in trouble. It is being attacked by a glacier. Since most of their settlements and cities lie along the same steep valley, they all drink the same water. And it is along this waterway that the Slow Fist, the Shatterwrack, the Glacier of Doom cruises along, crushing everything in its path. This glacier is one of the famous tools of the Uronothi.
The Uronothi are a hive mind of nimble zombies and dull-witted mortals. They come from the frozen mountains, riding mammoths, and things made from mammoths. The Slow Fist represents the leading edge of their forces. It is sweeping through the valleys and canyons, crushing homes into rubble and towns into wreckage. On this hypermobile glacier, the undead troll lord Ghorion represents the physical leadership--the brutality and domination. It doesn't matter what Ghorion once was. He is now a thrall of the Uronothi. He is the edge of the blade that is the Slow Fist.
Ghorion is eleven feet tall. Over the long, bleak years he has collected a great deal of powerful magic weapons. His rib cage is his armory, and his collection of magic blades emerges from his back, glowing with eldritch energy. When he wishes to draw a new weapon, he grasps the weapon's handle (at the back of his hollow chest cavity) and pulls it out. His forearms are likewise studded with enchanted daggers. His entire body is a sheathe.
Ghorion is bonded to an ancient Uronothi fort, now embedded in the roof of a glacier (by magical effort). A thousand years ago, the stone fort held roosts for the dragonriders of Uro. Now, the black marble towers are rimmed with frost, and jut upwards from the ice like the remains of a burnt forest.
As Ghorion takes damage, the towers will fall. If one of the towers is destroyed (and that would be quite the effort), huge wounds will open up on Ghorion. If one is destroyed, so will the other. If Ghorion survives the battle, he will have rebuilt the towers within a day--one of the abilities of stonebonded troll--and his body will have repaired itself to full health.
Even in his current state, Ghorion is still one of his mother's beloved. The Earth itself protects him, but not overtly. No manufactured weapon of stone or metal can hurt him, unless the weapon was crafted by immortal hands. This protection ceases when Ghorion is no longer in contact with dirt or stone (including his bonded fortress). This effect applies to all large pieces of stone or earth. If the party lures him onto the ice (for example) this ability will be nullified.
Although he is now undead, and therefor no longer has the regeneration that is endemic trolls, Ghorion still represents a sturdy mass of armored muscle. His rotting brain operates on a simpler level, imitating violence and clinging to self-preservation through sheer force of will.
Ghorion is a beast. While not intelligent, he is a clever, agile opponent, which will surprise those who were expecting merely another monstrously strong brute. Although, he is also a monstrously strong brute--all trolls are.
During the fight, he will attempt to knock players from the towers, or throw them onto the impaling spikes that line the battlements of the towers. Ghorion is fully capable of leaping the 50' between the towers, and can climb them like some shambling ape.
He is an expert in all weapons, unlike most trolls. Unlike all trolls, actually.
If the party has not disabled the undead dracolisk before challenging Ghorion, he will call for the beast, and it will fly from one of the old towers. The dracolisk is missing the upper half of it's skull--instead the head is a seat for a mounted pair of lesser undead armed with lances. Other undead cling to the inside of its skeletal ribcage, swinging long meat hooks and rusted pikes.
Lastly, he has the power to animate several of the weapons that stud his huge body.
The large scythe will spin in place and slowly move around the battlefield, creating a zone of slicey death.
The lance will hover beside him, parrying attacks against him and making it dangerous to charge him.
The greatclub will make huge arcs before slamming into the ground. While it is easy to avoid, it is devastating when it hits.
While Ghorion has dozens of weapons in his body, there are a few he prefers to fight with.
The Sharpest Hour, a glaive that can cut things from a distance and deflect arrows.
The Wheel of Ill Omen, a sentient, evil shield. It is round and covered with cutting edges. If thrown, it returns to its owner. The face on it can speak and enrage people.
The Jocken Blade. It is said that to be hit once by this blade is to know the power of the blade. To be hit twice by this blade is to know the fear of the blade. And to be hit three times is to die.
The twin hammers, Kallex and Kharn, which sunder armor and break bones.
So, I'm running a high-level Pathfinder campaign for my players. I know the usual complaint is that it is tough to challenge high-level PCs, because of the vast resources at their disposal. Which may be true. But it's also an opportunity to throw all sorts of insanely difficult stuff at them and then watch them triumph. The players get to feel like colossal badasses (which they are, at this point) and I get to give my imagination free reign.
The idea that he can only be hurt by weapons is initially intimidating, but easily bypassed. Ghorion is a clever tactician, but a poor strategist. If he is lured on on to the ice, he can be hurt by weapons. Flooding is a possibility. So is attacking Ghorion with things that were never forged to be weapons. A blacksmith hammer would hurt him, but a warhammer wouldn't. A practice sword would cut him, but a real one wouldn't. An arrow made only for competition would hurt him, but most arrows wouldn't. Or just stab him with skeleton ribs.
If the players aren't high level enough to provide their own work-arounds, they could find weapon that was not crafted by mortal hands (which leaves a lot open to interpretation, like robots???) or they could collect weapon-like objects that were not intended for this purpose. Or they could simply dynamite the buildings that Ghorion is linked to. Ghorion instinctively prefers his fortress-towers (and stony ground), but it would not be difficult to trick him onto the icy flats of the glacier (his brain is badly rotted, after all). Aside from his tricks, his ragged, undead body is very killable.
Ghorion is probably the coolest boss in this optional glacier dungeon-thing. I like him a lot, and I hope he dies an epic death.