All of those who took the road before you, they were possessed by the dark power
But you, you shall do this alone
As you walk through the valley of the Gorgonian Tempest
The tri-elemental black darkness was engulfing the sovereign lands
"Use the plus nine staff of the bobcat" a voice said from above
Defeat the Demon of Rathcorf and you will restore peace to the land and lineage of your blood
At the end of that one mission in Reach "The Package", as Carter is preparing to borad the Pelican, he tells Jun to esort Dr. Halsey to "Castle Base". So yeah, they went to castle base. I win!