I realize this guy is crazy powerful. This is my first crack at throwing together a dragon for Dungeon Crawl Classics by converting one of the 2nd Edition Linnorm (Norse) dragons. This guy, as he stands, is the campaign ender, one way or another. Characters that aren't already almost demi-gods themselves are likely to be wiped out, but thankfully, with his personality, if those good guys show up to slay him and run away screaming, he usually doesn't bother to come after them.
Kaldrvedr, Dread Dragon of the Barrowmounds
Kaldirvedr is thought of as a singular threat now, but the legends surrounding the beast suggest that it was once two separate beings, twin human clerics of the wintry gods of the northlands. The twins were two of the twelve heroes of the land, performing great deeds, slaying powerful giants and trolls, and bringing great wealth to their homes.
When a vile necromancer sought to enslave the lands of their birth, the Twelve Heroes set out to destroy the spellcaster, but they had just returned from a lucrative raid of a dangerous city to the south. With their ship laden with gold, they slowly sailed to face the necromancer before the bones of their ancestors could rise up to form an army to threaten the northlands.
When they arrived, too late for the weight of gold in their ship, ten of the heroes died fighting the hordes of the necromancer. When the twins prayed to their cold gods, the gods answered them, and told them if they but sank the ship of gold beneath the waves, that they would be given the power to destroy the army of the dead and the necromancer for good.
The twins had never seen as much treasure as this last raid had gained them, and they found it unfair that they should risk life and limb for this, their most bountiful raid, only to give it up to gods that should be willing to destroy this unnatural army without propitiation. Thus they sailed off to another settlement, further to the north, thinking to raise an army there to defeat the necromancer and scorning their gods.
A storm blew up from the arctic and tossed the ship, full of gold, upon the shores. The brothers fell overboard into the water, both fully in mail, and both thought to drown. Perhaps they did, but the dragon Kaldrvedr dreams of the lives of both of these young, formerly heroic priests, and dreams as if those lives were his own life, in the past.
A vast, two headed monstronsity, Kaldrvedr is serpentine in shape, with a long tail, two winding necks, clawed front legs, and massive draconic heads. His scales are black and grey, and hard as iron.
Kaldrvedr lairs in a vast cavern beneath the barrowmounds that were desecrated by the necromancer two hundred years ago. Other heroes came and defeated the necromancer, and laid a curse upon the barrowmound, containing the restless dead deep within the earth. The uppermost levels of the mounds have been consecrated to the gods of the north once again, with a single stone door, sealed with a rune, to lock away the restless dead.
Or a decade ago this was true. Rumors persist that tomb raiders broke the seal and stole the great treasures of the Ten Heroes, and then died within the barrowmound. The dead stalk the land again, and Kaldrvedr has awakened, and swims out from far beneath his lair, to wreck ships and then feast on them, crew, timbers, and all.
It is said that brave heroes entering the tomb are met with the spirits of the Ten Heroes, who will give those worthy a clue about the powerful arms and armor they possessed in life, arms and armor that can be used to fight Kaldrvedr. Would you know more?
Kaldrvedr, Old Dread Linnorm
Init +20; Atk +20+1d8 (claw 1d8 x 2, bite 1d12 x2, tail slap 1d20); AC 35; HD 20; hp 120; MV 80' (Swim 60'); Act 5d20; SP Breath weapon, frightful presence, magic resistance, weapon resistant hide, infravision 100', cause earthquake, dust cloud, gust of wind, curse, darkness, corrupt water; SV +20 (all saves); AL C
Breath Weapon: Kaldrvedr can breathe two separate breath weapons, twice per day for each head. This takes the place of one action die, and Kaldrvedr cannot breath with both heads at one time.
Cold Wind; Cone 60' wide and 40' long, 60 points of cold damage and knocked prone, Reflex save for half damage and to remain standing.
Steam Breath; Cloud 30' radius, up to 90' away, 60 points of fire damage, Fortitude save for half damage.
Cause Earthquake: See Dungeon Crawl Classics pg 409, DC 30. Kaldrvedr can do this once per day, and this replaces one of his action dice when used. Kaldrvedr often uses this to seal his lair behind him when he enters or leaves through the sea cave.
Corrupt Water: At will, Kaldrvedr can turn all water within 100' into poison, that causes 1d4 hit points damage per sip, avoided with a DC 30 Fortitude save. This replaces one of Kaldrvedr's action dice.
Curse: Once per day, Kaldrvedr can curse a single creature for 24 hours, causing it a -1 to all rolls. This replaces one of Kaldrvedr's action dice.
Darkness: At will, Kaldrvedr can create darkness in a 30' radius up to 100' away. This replaces one of Kaldrvedr's action dice.
Dust Cloud: One per turn, Kaldrvedr can summon a dust cloud 10' wide and 50' tall. All creatures within must make a DC 30 Fortitude save or take 1d4 Stamina loss. This lasts as long as Kaldrvedr concentrates, and an additional 1d4 rounds. This replaces one of Kaldrvedr's action dice.
Frightful Presence: All who look upon Kaldrvedr are terrified by his power, and must make a DC 30 Will save for flee in terror for 1d4 turns.
Gust of Wind: Once per day, Kaldrvedr can summon hurricane force winds to blow in a singe direction, 100' wide at the end of the cone. Creatures caught must make a DC 30 Strength check or be blown back 200 feet and taking 20d4 damage. This replaces one of Kaldrvedr's action dice.
Magic Resistance: All spells have a 50% chance to fail when used against Kaldrvedr.
Weapon Resistant Hide: Normal weapons only do half damage to Kaldrvedr's armored body. Magical weapons can harm him normally.
Tactics: Kaldrvedr will actually ignore anyone that is turned aside by his frightful presence, amused at their terror. This means that adventurers that wander into his lair unprepared may live to fight him again.
Once anyone from a party has attempted to harm him, he will fight without mercy. He will usually alternate a breath from each head while attempting to rend would be heroes asunder, and then will summon a dust cloud to choke his foes while he batters them with his tail.
If he feels that his foes are doing too well, he will use his last two breath weapons, and may attempt to flee out of one of his holes into the sea caves, collapsing it behind him using his Earthquake ability, then spending time once the coast is clear digging the entrance out.
Kaldrvedr has mounds of treasure brought to him as tribute, but cares little for it. Anyone bearing an item of the Ten Heroes, however, will be marked for death.
The Barrowmounds: Within the sealed sections of the Barrowmounds are the weapons and armor of the Ten Heroes. In death, their spirits imbued these items with the means of defeating Kaldrvedr. Some items turn aside the fear he generates, and others are anathema to his flesh, and still others might steel a warrior against cold or ice. Finding these items may be the key to surviving the dragon and ending the curse of the Barrowmound by killing the dragon bound to the necromancer's hordes.