Relic castle is located in the northern end of desert resort. To reach it, simply head west from the north end of route 4, then head north once you see the doctors. The entrance is marked by several blue Darmanitan statues. Before finding N in Dragonspiral tower, the only thing you can do in relic castle is retrieve a fossil of an ancient Pokemon to revive in Nacrene city's museum, but after meeting N in dragonspiral tower you can progress deeper to find the Black/White sphere and TM30 Shadow Ball. After becoming the champion, you may return again to get TM26 Earthquake and find and catch a Volcarona.
there is a backpacker in relic castle who will give you either a plume fossil (which is revived into an archen) or a cover fossil (which is revived into a tirtouga)
at the end of it
Volcarona is inside Relic Castle.
It's in the Agate village and is close (left to and below) the Pokemon center
The Relic Castle is on route 4 where you have to go left and then up again.
Relic Castle
Desert Resort.
Relic Castle
you don't "pass" relic castle you go to it later and meet team plasma (you also get a fossil if you talk to the backpacker!)
By trade.
if you go down to the very bottom of the relic castle go up the all the stairs and you should be out. hope this helps! =)
there is a backpacker in relic castle who will give you either a plume fossil (which is revived into an archen) or a cover fossil (which is revived into a tirtouga)
in the desert resort
relic castle
In relic castle
route 4 or relic castle
at the relic castle