In my experience, there is nothing—nothing—players hate so much as an NPC or monster they think should be on their side but isn’t.
Here’s an experiment: Have an NPC steal a valuable magic item from them, torch their home village, send them to another plane, and then resurrect after they finally kill him.
Now have a paladin reprimand them for breaking a church window and charge them for healing.
I guarantee you they will be sputtering curses at that paladin to their graves.
So the jyoti will drive them absolutely insane—especially if you’ve primed them with some nasty Negative Energy Plane encounters so that they associate Negative with evil. Naturally they’ll make assumptions about the goodness of the Positive. Give them a run-in with some shadows or sceaduinar or a lich or two…then shift venues so they discover the bright wonder of the Positive Energy Plane…let them bask in the warm, healing power of all the potential energy in the universe…
…And then introduce them to these xenophobic jerks and watch the feathers fly.
The jellyfish-like construction of the Solar Skimmer seems perfect for exploring the brightness of the Positive Energy Plane—but its light and airy decks are little protection from a flight of jyoti. They attack the Skimmer’s crew and abduct any divine spellcasters for incarceration and exile.
An adventurer suffers a wasting disease no cleric can cure. His friends take him to the Positive Energy Plane to recuperate. There they stumble into a planar politic crisis—a sun deity of their world is attempting to establish a mission in one of the jyoti’s crystal cities, and the jyoti have sealed their world’s gate of souls in answer.
The sceaduinar claim the jyoti stole the gift of creation from them. In at least one reality this is true—but the sceaduinar have taken it back in the form of writing. Though words on parchment are of little use on their umbral plane, a few sceaduinar who took the time to study their foes the undead realized what store creatures on other planes set on these ink scratchings. They have commissioned their story, the story of the jyoti’s crime, to be published—and the jyoti, incensed, have launched a multiverse-wide crusade to burn every copy.
—Pathfinder Bestiary 2 171
Have you sent me your dice rolls yet (details here)? Get on that!
What I said above about hating paladins? Dude, that included my paladin. My double-sword-wielding, fire-resistant, laid-on-hands-whenever-they-asked paladin of Iomedae that they made baroness (Kingmaker Adventure Path) over her (and my) objections because of her high Charisma…and then immediately started to loathe for no reason. It was so galling. And before you think it’s me (a fair suspicion), they had no problems with my slightly haughty elven eldritch knight, my blatantly chauvinist rogue, and since I’ve taken a few weeks off they keep asking when my halfling cleric (secretly of Calistria) is going to come back.
Meanwhile, to this very day they refer to my paladin as “George Bush.” The mind boggles.
(She even let them have a brothel provided it was unisex and the staff well treated. Still: George. Bush.)
(The worst part was the campaign concluded while I was in on vacation for three weeks in Australia, culminating in encounters with both a demon and a red dragon that she was basically specifically designed to fight. I nearly sobbed when the GM told me I was a week late.)
“Jyoti” means “auspicious flame” in Sanskrit. Well played, Paizo. Note to all Forgotten Realms monster designers: yes, you can do more than just combine random syllables.
And I didn’t even mention their breath weapons or spell-like abilities or ghost touch weaponry or…
Flo was awesome. I was stunned at how packed the place was—somehow I hadn’t quite grasped (though I should have) how big she’d blown up. I also had never seen her live, so I was expecting a Tori-style woman/piano/band rock show, not a full-on operatic pop spectacle. (I was likewise stunned at how earnestly over-the-top she was—none of the winking, I’ll-take-the-piss-out-of-myself-before-you-can that I expect from British musicians. Then again, if you rise quickly and unabashedly enough, the Brits will sometimes give you a total pass, earned (Flo) or not (Oasis).)
And the night was perfect, too—I’m now regretting not getting Metric tickets for Friday. I told myself I couldn’t handle two goth-pop acts in one week, but the just-slightly-crisp September night was so amazing and energizing maybe I should change my mind.
(And before you Flo fans bristle at that “goth-pop” label: 1) there was a harp and two drummers, 2) she ordered us around like a prim but demure dominatrix, 3) she had us put our neighbors on our shoulders as “human sacrifices,” and 4) she invoked the moon and stars while plaintively gesturing toward the actual moon and/or stars. Happy goth who likes colors and trees, but still: goth. The fact that Wikipedia calls her indie rock (especially after a #2-charting debut album) is a joke. There hasn’t been a star that so totally fooled her suburban North Face-wearing audience since a band called Queen successfully convinced America they were an arena rock band and not a Provincetown lounge act. (Seriously, when I get my time machine, just before I go kill Hitler, I’m hitting the ’70s to give Freddy Mercury a high five.)
All of which is to say, go see Florence + the Machine. She—or rather they—are awesome. But don’t tell yourself you’re seeing Slint. You aren’t, and that’s perfectly fine.