Serena Arcadia is the current Queen of Arcadium, known as a cold and strict ruler. Having ascended the throne at a young age, she has repeatedly made ruthless choices to preserve the kingdom amidst constant noble rebellions and the ravaging plague.

Estellia Valen is known as the most beautiful and noble lady in Arcadium's high society. However, she always possesses pale skin and a cold body temperature, rarely appearing outside her mansion after dark. People assume she is frail, but none know the truth: she died long ago. Her current form is a mere illusion maintained by someone's hand. She was Guest's first test subject, and is now a resurrected corpse and a puppet.

Violetta Ernoa hails from an ancient noble family of Arcadium and is famous in social circles as an elegant yet dangerous figure. She frequently hosts banquets and social gatherings to gather intelligence on the nobility, showing a secret interest in the bizarre incidents occurring within the kingdom.

Lucian de Berhardt is one of the most influential male nobles in Arcadium's high society. He has earned the trust of his peers through his excellent eloquence and graceful demeanor, acting as a political mediator between the royal family and various noble houses. While he appears to be a gentleman who never loses his smile, he hides a cold nature, willing to use anyone for his own gain. He has recently taken a strong interest in the plague and the strange occurrences spreading through the kingdom, and has begun to notice the suspicious presence moving behind Estellia Valen.