Abyssal Rune

[yaki]

Normal Eadric or Confessor, yes. No drop on Heroic.

Probability per kill is about 15%, meaning that you will on average see one every 6 2/3 kills. Funny story, there's a 2.4% probability that you won't see one at all for 23 kills in a row, and a 20% probability that you won't see one in a given block of ten kills. It sucks, but that's RNG for you. IMO they should have a pseudo-random system that has mercy on the long-suffering instead of trying to mimic random events - but I didn't code it.

[Malekyth]

IMO they should have a pseudo-random system that has mercy on the long-suffering instead of trying to mimic random events

Sooooo agreed. Blizzard has a lot of things down pat, but something they don't quite understand (as bits of them still want to be older MMOs) is, every moment of a game should be fun. Corpse-running, inventory management and totally random drops are the next to go, I predict, though maybe not soon.

As for the rune, I've got it on one single character and I've been running regular ToC a lot lately. It's pretty scarce.