Well, here's the thing it seems nobody has mentioned yet. I got super excited when I came across this chapter because HOID is in the engravings at the beginning of the chapter. But in my initial readings of it, it seems that he's not there -- that *thing* is, instead... unless, as @Wreith has said, perhaps it's HOID helping her find the thing...
In the past, it has been noted that either HOID is in the chapter when this masked man appears or at least people looking for Hoid. So, where is Hoid here?