Our first imperial dragon, courtesy of the Bestiary 3! There are lots of ways to handle the imperial dragons, depending on your campaign. Maybe they’re just yet another branch of the dragon family, albeit with some nifty/nasty special abilities and breath effects. Maybe, as in Naomi Novik’s Temeraire series (and as is implied in Paizo’s various Golarion products), they are actively engaged in shaping human societies, unlike the more secretive or standoffish Western dragons. Or maybe, given their polar alignments, they are signs, signifiers, and enforcers of greater cosmic principles—nearly semi-divine beings.
Meanwhile (egad, yet another two-paragraph intro!), forest dragons can be just a regional result of the dragon flowchart: “Let’s see…evil, setting is vaguely Asian, adventure takes place in forest…forest dragon.” Or you can throw them pell-mell into your typical Pathfinder campaign. How would lawful greens react to the stronger chaotic competition? How would elves adapt to defending against two kinds of evil wyrms? How would other earth powers like a blue dragon or shaitan respond to the forest dragons’ close connection to its element?
A forest dragon and a coven of green hags play a game of chess using a whole forest as a board. Agreed upon landmarks and vegetation from the squares, other woodland denizens are their game pieces, and adventurers their pawns. Naturally, both sides also cheat whenever possible.
To Western adventurers, a grove of petrified statues of pain-wracked corpses seems to clearly be the work of a medusa. But hunting reptilians is likely to only anger the local nagaji (Dragon Empires Gazetteer 10). If the victims are restored to both flesh and life, they can attest that the real culprit was an ancient forest dragon who took their promised tribute offerings and then slew them anyway.
As long as anyone can remember, a mysterious greater earth elemental has appeared once a month to clear stones away from an avalanche site at the base of a wooded mountain. Intrigued and hoping for treasure, the local hidalgo has encouraged villagers and nearby monks to aid the elemental’s work. If they do, they will find no good deed goes unpunished—the avalanche conceals a buried forest dragon. Traditionally called by the dragon’s breath, the elemental now responds to the hibernating dragon’s instinctive mental cries for aid even across planar boundaries.
—Pathfinder Bestiary 3 94–95