I have been doing the hero challenge stuff almost daily ever since it was added as a feature..
But i noticed that the 4 types of runes dont drop evenly.. in fact currently i have 11, 4, 0, 3 legendary runes.. (meteorite 11, celestium 4, primeval 0, everflame 3).
Its very hard to upgrade anything like this
Is it a bug or meant to be a micro transaction thing?
Also i noticed that i get alot of the first kind of runes for no particular reason.