Neet
"There are people of Neet, and my mother, sleeping here."
Neet, Mille Seseau was a quiet little village east of Deningrad. It was close to a deep port capable of docking ships. It was this town that both Zieg and Claire ended up settling in after their long journeys. It was the hometown of both Dart and Luanna. 18 years ago, the Black Monster destroyed the town and killed everyone but Zieg and Luanna. Its target was the Moon Child Louvia. While Louvia had already fled the village with her nanny and royal guard, the Black Monster could not let anyone survive to avoid them becoming servants of the Moon Child.
At the present time, Neet was a forgotten memory that only those alive during the time would remember. Either both Princess Louvia and the destruction failed to leave an impression on the new generation or the topic is practically taboo in conversation.
Unlikely Meeting
"Nothing has changed. (Am I... hesitating?) It's silly."While the party travelled to Deningrad, Rose left temporarily. She did not tell anyone she was heading for Neet, likely because no one was aware that she had any attachments to the ruined town. Dart did not return to Neet, though you can visit after Rose does. There are no additional events however, possibly implying Dart had already come to terms with the events in the town and had no problem visiting the ruins. It was unknown if Rose visited the places she destroyed in remembrance or if Neet was a one time event spurred by the events on the Ghost Ship and her own conflictions regarding Dart.
It was obvious from Rose's first words that she had hesitations about returning to Neet. These were likely caused by Dart. While she had come to an understanding about her feelings about Dart and recognized she did not care for him in a romantic fashion, it was her relationship with him that caused her hesitation. Rose likely never interacted with survivors before or never interacted with them at the level she had with Dart. The apprehension she felt was likely guilt due to her actions that resulted in his loss of parents. Rose did not regret her actions in the least however this did not mean she enjoyed destroying people's lives. After all, Rose's actions as the Black Monster were to save the very people she kills.
Rose met the Sacred Sisters Luanna and Setie at the memorial located in the town. The memorial was created to give people a place to pay their respects to the people who died in the town. However it seemed knowledge of the town's destruction has faded though the years and very few people remember its existence. It did not seem to be a taboo subject as there was a collection of artifacts from the town at the National Library. It's more likely no one wanted to be reminded of the destruction and simply chose to forget.
A Child's Past
"I... I can't see. Mom, I'm scared. "When the two asked Rose if she was visiting the grave, Rose replied with "I guess so." It was likely she didn't intend on visiting the grave specifically but her actions were more or less the same. During the conversation there was a flashback of the Black Monster confronting Luanna and her mother. It was Luanna's mother that revealed Princess Louvia had already left the city on a boat and told the Black Monster to leave. It was then revealed that not only did the Moon Child have to die, but all those around it to ensure no one became a servant and assist it to the Moon That Never Sets. Luanna's mother was subsequently killed. However Luanna was not killed by the Black Monster. Their home was already on fire and it's possible Luanna was left to die in the fire. She was also blinded that day, though it is unknown how her eyes were damaged. In any case, it's likely Luanna was never intended to survive and her survival was not mercy by the Black Monster.
The flashback was likely Luanna's though Rose would naturally have the same memory of the event, only without the knowledge Luanna was blind. Luanna explained she was given the ability of see into people's souls and she used this to help people overcome the pain in their hearts. She offered to help Rose however Rose declined. Obviously this would be due to the fact she was the Black Monster. Rose also closely guards her emotions and feelings and would not want someone privy to her thoughts and secrets. It was unknown if Luanna is able to look into the soul of a person without permission. Though from their interactions, it seemed Luanna respects the privacy of others and was therefore unaware that Rose was the Black Monster.
Protection
"May I join you? Even if you are with knights, the forest is filled with dangerous monsters. I can protect you from them."
Rose offered to protect Luanna on her way back to Deningrad even though she was with her knights. It was possible Rose felt a need to protect a survivor of her carnage. Even though Rose went to Neet, it ended up being about Luanna more than about Rose. However though her interactions with Rose it became obvious that Rose did not enjoy her actions as the Black Monster and her relationship with Dart was revealing more and more of her true self.