Key to Rivenpeak

Castle Rivenpeak lays on a planar fault line.
The fractured ley line the gives this threshold
its arcane energy. Its the only way in or out for
the local planes; Prime, Shadowfell and
Feywild. Certain gems can focus this power.I
think I found such an indestructible stone. We
shall know more after the Magos experiments.
-Journal Entry, Henrik von Helgebrand