I have been running through this area A LOT in the last four days to fight wavebringer to replace my Life Deck that I accidently sold and ran accross a game stopping glitch.
After defeating the bosses in the Fire Shrine and then lighting the shrine, I have been pulled back into a battle with the no one. When this happens, there is no option of choosing an attack or even the choice to flee... Just me in a battle circle with no one to fight. This has happened on several occasions which makes the area impossible to do alone.
As if Wavebringer isn't challenging enough to get to, it is very frustrating running all the way to Haru and defeating him, then working the shrines, only to have to restart.