Whatever Marianne did to Iron Star because it certainly could not have been pleasant for her to say that “they probably wish they were dead” with the way she left them and then tells Kallen she’d be better off not knowing the details.
The vast majority of the Unistrad arc considering it's meant to be Fairy Tail meets the horror genre. To wit:
The first two chapters give amazing build up with tension so taut you can cut it with a knife. One reader even thanked the author for their nightmares.