Some parallel worlds have different time-flows, like the fabled dwelling-places of the elves: those who visit them under the hill for a night return to find that years have passed in this world. Perhaps it is the gate leading between the worlds which causes the alteration. If a gate were 'misaligned', the shift from '| |' to '| \' or '| /' as it were would lead to that difference, much as a light-beam split and bent by a prism ends up taking a longer path. There might even be a mathematical function linking degree of misalignment to alteration of time-rate.
The Black Forest- actually a part of another forest, is said to be cursed by the presence of some horrific monster, which burns the very earth with its body!
No one has yet seen it and lived to tell, so be warned!(see NPC Aurelius Blackfoot for details)