The Core room is the room housing the magical crystals that power the capital city and keeps the barriers up.
r u l e s . . .
o1) As mentioned, Yggdrasil is a fortress. It is heavily guarded,
with layers of magic, and you can only pass through the three
entrance/exits that cross over the band of water surrounding it.
Unless you wish to risk cross the mountains. No intruders, and
that means no spies either.
o2) No one, and I mean no one, save the king is allowed
inside, unless he has given permission to do otherwise.