You have pledged to lend your aid and your adventuring skills to Durin's Folk and fight on their behalf in Mordor.
'Messengers have come from the Iron Garrison, ${PLAYER}! There is trouble afoot in Khazad-dûm, and the king is sending me with a group of warriors to come to their aid! Quickly, speak with King Thorin and see if he wishes for you to come with us!'
Foldgráf is assembling a group to come to the aid of the Iron Garrison, in Khazad-dûm.
Bósi is in the Hall under the Mountain. Khazad-dûm, and much of the Iron Garrison, is lost.