Whenever we talk about celestial creatures and adventure seeds, there’s always this tension between “Will they be so good and helpful there is no reason for the party to ever fight them?” and “Will they be so snooty and removed there is no reason for the party to ever engage with them?”
That’s not a problem with peris. Peris are the descendants of fallen angels. Players can get behind that. Peris are good, but not near-perfect the way angels are. Players can get behind that. Peris seek redemption. Players can get behind that.
And most importantly, peris like fire. A lot. Fiery wings! Fiery flame jumps, whirlwind dances, and a host of spells. Cleansing fire it may be, but still: BOOM. Adventurers like BOOM. They’re going to love peris.
So if your PCs need a hand fighting some divs or oni or other fiends, a peri will likely be happy to help. And on the other hand, if a peri gives way to the same evil that defeated her forebears, PCs can have a grand time rescuing her—or putting her down—in order to save her soul.
Captured by a foul div, the peri Jazmina has been trapped deep below the earth in a cage of cold iron, to be taunted and tormented by fiendish ropers. Sadly, rescue won’t help—her mind snapped long ago, and if released she will fight even her saviors to the death.
Though they do not speak of it to outsiders, Clan MacTeague features a number of emberkin, all of whom trace their line back to the peri Caerdwilla, whose mother Una the True fell and become the Bog Crone of Lies. If adventurers cross swords with any of these flame-haired children (ginger, that is, aside from one who has actual flaming hair), Caerdwilla is sure to cross scimitars with them.
Adventurers hired to guard a priceless artifact are unaware that they are actually helping an efreeti transfer a sacred marid relic to an asura to be destroyed. When a peri comes to claim the artifact, will she be able to persuade them of the rightness of her cause, or will the adventurers’ oaths of service (or their brash arrogance and bloodthirstiness) rule the day?
—Pathfinder Bestiary 3 216
I claim to be all about story and lore and theme…but ask me about my flying eldritch knight who once took out an ulgurstasta almost single-handedly. BOOM.
Also, if you like your aasimar peri-flavored, check out Blood of Angels, which has stats for several variant aasimars, including the peri-blooded emberkin.