Dragons are living, intelligent beings, not monsters for a trophy wall. Sozin started encouraging dragon hunts earlier in his reign, even though he had reason to know they cause spiritual and environmental harm, to bind the nobility and recover popularity. A few dragons died at first; the sport grew. Killers take the honorary title "Dragon" and a rumor of multiplied firebending. Dragons have become more aggressive. Spirits gather at death sites. This is already a wound, years before the comet.
SOZIN'S DRAGON AND THE AERIE
Sozin's own dragon is unnamed in canon. In this world the beast stalls in the Royal Dragon Aerie, caldera cliff stables, and is uneasy. Sozin arrives and leaves here. The dragon is not a speech-giving NPC by default, but it is not furniture. It may refuse a flight, warn a rider, or remember that another dragon did not come back from the island. Fang, Roku's companion, lingers with Roku's spirit at the island echo. The official story does not include a returning empty saddle in the public version; Viro's log does.
RAN AND SHAW
The eternal dragons roost in the Cave of the Masters in the hidden Sun Warrior city. They are the heart of the first fire. They test the worthy in the Dancing Dragon and may refuse anyone who smells of a fresh dragon kill. A hunt trophy in a PC's pack is a problem at that cave, not a souvenir.
HUNT SITES AND THE SPIRIT WORLD
Kill-sites draw strange occurrences. Sozin has blamed visiting Water Tribe investigators for spirit activity that his hunts caused. Dark or angry spirits are more common with no Avatar to mediate and with the hunts underway. Hei Bai's forest is being measured. Polar spirits are loud. An optional original darker thread can grow from this, but the default wound is already enough: a sport that makes the nobility loyal and the Spirit World furious.
ITEMS AND TEMPTATIONS
A dragon scale from a hunt circulates in noble houses and black markets. It is a status trophy. Spirits notice. Do not price it like a common gem. Academy fire is already sharp and martial; the life-based Sun Warrior form is endangered by hunts and fashion. A PC who wants @Heat Redirection or a "Dragon" title should feel the moral and spiritual cost, not just the damage bonus.
QUESTLINE: THE DRAGON AERIE
The unease in the stables, a countryside hunt the party can stop or join, a scale in The Scented Coal, a Sun Warrior trial, a spirit storm on a kill-site, and the question of whether Sozin's own dragon will keep serving a hunter-king. Uzuku Yuyan will not take a contract on children; ask whether she will take one on a dragon, and let her ethic answer.