There is only one solution.

You must go inside it yourself... inside my nightmare.

The Daeva of Psychic Arts, Bridget, will help you enter the nightmare.
So the only option is to go into the Nightmare?

(Considers you carefully.) If you enter Cheska's nightmare, you will be completely cut off from the outside world. That means nobody will be able to help you.

I advise you to prepare well.

Do you want to start right now?

In that case, take my hand. I will take you to Cheska's nightmare.
So the suffering of the people in the Kaliga Dungeons were what was causing the nightmare.

And the overpowering thoughts came from Robstin and Kromede.

You avenged her in the dream, so those thoughts and nightmares should trouble you no more.

Thank you!