>>720198198
If you dont mind the minor spoiler the mist is the alternate entrance to the citadel, basically the backdoor if the boss from the end of the climb filters you
You can get through there by playing the needolin for the little lightmoths. They will lead you in the right direction
Dont worry about the deep docks place, there isn't that much there besides a new tool
Good luck on the final stage of the climb!