User blog comment:Miskos3/Fairy Tail Chapter 508: Pleasure and Pain, Review/@comment-5303512-20161031153910

Well that was certainly an interesting chapter, I guess that this confirms that Larcade's magic is very much akin to that of the Rapture, the joyful feeling before departing this world. But it is interesting that there are a few people uneffected, perhaps they have strong willpower to not give into the pleasureful effect or maybe magic that resists them, like Wendy's ability to remove any foreign forces. But the next few chapters, I bet Sting is going to get involved somehow, then Larcade will reveal to have some sort of immortality like Zeref's.

So I guess it effects people who has sinned and those who are easily septiple to temptation.