Ancient scaled terrors of treasure, poison, fire, wisdom, and doom; in Norse style they are often serpentine wyrms as much as winged dragons.
For a Viking-inspired campaign, dragons work best when they are rare and story-heavy. A wyrm may coil under a barrow, gnaw beneath roots, poison a valley, or sleep over cursed gold rather than patrol the sky like an ordinary predator.
Níðhöggr gnaws below Yggdrasil, and Fáfnir becomes a dragon through greed and cursed treasure. Norse dragons often connect wealth, death, venom, and fate.
Use dragons as campaign-shaping threats, cursed hoard guardians, ancient powers below mountains, or legendary comparisons for lesser drakes.
Most dragons encountered in the current Latitude record appear to trace back to the far-northern Aetherstone Islands, where Aetherstone is mined and small dragons eat the floating stones. That origin helps explain why dragons are rarely seen in the settled fjordlands now: the surviving populations are concentrated far to the north, and the location of their islands is deliberately protected by those who know it.
DM-only encounter details, stat blocks, and running notes are kept at Dragons / Wyrms (DM).