This occurred to me yesterday while I was driving in my car that during the StB Hildibrand questline, we see that Gilgamesh opens his dimension portal to escape and Hildibrand goes into it. Then we see Hildibrand in The First when doing Heroes’ Gauntlet.

So if Gilgamesh can create portals to other places like The First, it’s perplexing that we couldn’t use him to help us open a portal to the 13th. Better yet, Y’shtola could even go to him if she ever wanted to see Runar again.