I see. Sorry for the mixup.

" I can't seem to edit, steam keeps telling me I can't"

As you said, I should, but I can't. I am not the real creator of the guide but I am the most active out of the 3 of us that run the guide so it is quite troublesome.

Okay cool thanks breh, you should include this in the guide lol

Just before the Kratarac fight, you have to use boost wings to go up, instead of going up-right stick to the left where you can see dark fog, if you do it right the fog will go away. From there keep going up and you will be in a room with a flying idle enemy and the chest on the right, just double jump to get past the dark holes and flutter as you are falling (don't forget to kill the enemy too, or you can use its knockback).

Where in the underworld do you find this outfit?