So is Satan just generous when people don't have a soul to sell? maybe if you do enough deeds in his name...

"It's hard to be religious when certain people are never incinerated by bolts of lightning."

— Calvin, about Moe, Calvin And Hobbes

Sometimes, even Laser-Guided Karma misses its target.

The character has done a number of things that deserve a karmic comeuppance, most importantly things that caused harm to the innocent, but when the time comes for the Karmic Hammer to fall, that's not what happens. He doesn't get what he deserves. Instead, he gets away scot-free.

This is it. This is all there is to the story. The show is over. The book is finished. The author isn't going to write any more. The Word Of God has been spoken. The guy has become a Karma Houdini.

Compare Butt Monkey, for which a character ends up having many disproportionately bad things happen to them throughout the story (and may also technically qualify for this trope, as hard as that sounds). The extreme counterpart of that trope, Cosmic Plaything, can be considered this trope's polar opposite.

Contrast the aforementioned Laser-Guided Karma, for instances where the villain's comeuppance is swift and immediate.