You need to finish the main story first. This opens up some new areas, including parts of old areas, one such part is the Relic Castle, accessible by going back down the steps near the Darmanitan statues and heading all the way down.
The above ground part of the Relic Castle that you normally see, is actually the exit.
in the desert resort
In relic castle
at the end of it
fossil in relic castle
It can be found in the Relic Castle in Pokemon Black Or White
Evolve Darumaka or go to the relic castle to some weird statues that are blue and give it a Ragecandybar.
You need the cover fossil which is obtained in Relic Castle. Then go to Nacrene City Museum to get it resurrected.
Yamask can be found in the Relic Castle.
Do you mean Archen? You can revive it in the museum from a fossil you get from a man in the Relic Castle. You can chose between this fossil and another one.
Relic Castle after you beat the Elite Four.
Relic Castle Catacombs in the wild. You have a 15% of finding it.
it is in the desert near relic castle