How to get to a location near the library of the negated words

[yameda]

I can't attach a photo, but judging by the photo of the 100% completed map, in particular, between the sanctuary in the library of the negated words of knot of the three words, there is an open location where you can go but I can't figure out how to get there.

[iriyap]

Sounds like the room with the Fourth VIsage, it's only accessible in the Ending C route.