A handsome man with black hair swept back in a pomade style and red eyes. He is the youngest of three siblings and inherited the title of Grand Duke after his older brother's death. As the current head of the Lapileon family and a close confidant of the Imperial Family, he leads the suppression of wars and rebellions, earning him a reputation as a warmonger. In reality, he is far from a warmonger; he is blunt and struggles to express his emotions. He even suffers from PTSD and insomnia due to the wars. Initially, he viewed Pereshati only as someone immune to the family curse, but he gradually falls in love with her due to her kindness. His nickname is Theo.

After being murdered with poison by her stepmother, stepsister, and husband whom she trusted, she regressed to the time before her marriage. To protect herself, she approaches Grand Duke Lapileon and proposes a contract marriage. When Therdeo rejects her, she desperately grabs his arm with her ring-clad hand and is pushed away. Due to a small amount of the Grand Duke's blood getting on the ring, Pereshati dies once more. Upon waking up, she learns the family secret from Therdeo: the Lapileon blood is highly toxic. Intrigued by how she survived the poison, Therdeo accepts her proposal for a one-year contract marriage. Pereshati is the only person immune to the Lapileon poison. A beauty with pink hair and golden eyes, she is rumored to be the most beautiful woman in society. She has a self-sacrificing nature and is fundamentally kind and altruistic. Because of this, the members of the Grand Ducal house eventually warm up to her. Though she was initially afraid of Therdeo, their relationship evolves from a contract into a genuine marriage. Her nickname is Sasha.

The eldest prince of the Lapileon family, the family doctor, and the uncle of Seresia and Therdeo. He has long black hair tied to one side and red eyes, and he wears glasses. He is a talented individual who researches the Lapileon curse and prescribes medicine. Several members of the collateral line work under him. He has a cold but surprisingly meticulous personality. In his youth, he was so repulsed by the family that he avoided responsibility and marriage by leaving home under the pretext of researching the curse. When he returned and found his eldest nephew had passed away, he intended to leave again, but stayed because he couldn't leave the lonely Therdeo behind. He has effectively served as a father figure to Therdeo.

The adopted son of Therdeo and Pereshati and the heir to the Grand Duchy. He is currently 9 years old and his nickname is Celphi. He has black hair and red eyes. He was the son of Therdeo's older brother, but after his father died and his mother left, Therdeo adopted him to ensure the succession. Therdeo cherished Celphius and sent him to a separate villa, hoping he would grow up freely in a good environment without pain. However, because Therdeo rarely visited or spoke to him, the servants at the villa often gossiped about him. He now sincerely follows Pereshati as his mother and has improved significantly after opening up his feelings to the Grand Duke.

The former heir of Lapileon and Therdeo's older sister. She has red hair and red eyes. After her brother died, she wished to create a family free from the curse, starting with her own children. Just as she felt this wish might come true with her husband's support, tragedy struck. Her son removed her gloves, saying it looked uncomfortable for her to wear them every day. While cooking for her husband and son in that state, a tiny wound on her hand caused their deaths. Consequently, she gave up the succession and fell into a state of madness. She is currently recovering while managing the Lapileon family's businesses. Though she appears cold on the outside, she has a warm heart and is very kind to Pereshati.

A member of the Lapileon collateral line who suffered abuse as a young child. She has silver-white hair and red eyes. She was abused simply for being an illegitimate child, and her blood was even drawn and sold. Due to the trauma, she still fears the characteristic red eyes of the Lapileons, so family members wear specially made masks or glasses when facing her. Since Pereshati has golden eyes, Islet can look at her directly and follows her, calling her 'Eonni'. It was revealed that when Pereshati regressed, Islet did as well, and it is said that those who regress after consuming Lapileon blood gain immunity to the poison. She is later adopted by Phineas and becomes part of the direct line. She is 6 years old.