The religion believes in reincarnation, but that you will be reborn in the past. People of today are those re-born of tomorrow, with some discarded as trash. The most pure will be eventually reborn in the mythical paradise-like past, where people lived for hundreds, or maybe even thousands of years.
This goes nicely with beliefs into foresight (you know a little about the future because you have been there), but also to many complaints of how things are going always from bad to worse.
Finally got the idea for an orcish currency:
A cold-hammered piece of raw iron, resembling some kind of a dagger. The Dagger is easy to carry, hard to forge, may be used as a crude weapon in case of emergency AND the iron being a valuable resource... may be used directly for weapon-making. May be carried openly on the belt of a mighty Orc. A new insult: 'to beat someone with someones money' . Self-explanatory.
The party has found the source of the strange creatures roaming the countryside. The rift in this reality glows with a silver hue, rippling with the wind but never moving. They step through and are immediately assaulted with the scent of rotting meat, some have to muster all their strength not to vomit. Strange cries similar to the beasts the party had faced before can be heard in the distance. Looking around, they see they are in a forest of grey and red rather than the normal brown and green. The trees are sticky to the touch and writhe, perhaps to get away or perhaps as a warning.
The deeper the party goes, the more the forest seems to slither and move underfoot. The cries get closer and more numerous. Creatures lurk in the shadows, all the same color of their surroundings. Whatever the party came in here for, they had better do it fast.
The forest of flesh is waking up, and it is so very hungry.