Well, it could develop through shared experiences. Say the human got involved in Sebastian's work in some way. They might have to work together to solve a mystery or face a common enemy. During this time, they would get to know each other better. The human might not be afraid of Sebastian's demon nature, instead, they would be curious and try to understand him. This mutual understanding could be the foundation for a love story to develop. Also, physical proximity due to these shared tasks could also play a role in making them closer.
Sebastian's love, if we can call it that in his rather complex relationship with Ciel, is a very dark and twisted form of devotion. It starts from his contract with Ciel. He is bound to protect Ciel until he achieves his revenge. His 'love' is more about his loyalty to the contract at first. As the story progresses, he becomes more and more involved in Ciel's life and his emotions start to get a bit more complex. He seems to have a certain possessiveness towards Ciel, not in a romantic sense in the traditional way but more like he is the only one who can be by Ciel's side according to the contract.
Their relationship begins with the contract. Ciel, in his quest for revenge, summons Sebastian. As time passes, Sebastian becomes an essential part of Ciel's life, protecting him from various threats. Ciel starts to rely more and more on Sebastian, and Sebastian is always by his side. They face many challenges together, which deepens their bond, though it remains a master - servant relationship based on the contract.
In a Black Butler Sebastian love story fanfiction, a good match for Sebastian could be a librarian. She is well - read and can engage Sebastian in intellectual conversations. She also has access to a lot of knowledge about the occult and other things that might interest him. Another possibility is a young journalist who is always seeking the truth. Sebastian would find her tenacity and curiosity appealing. Or perhaps a female bounty hunter. She has a tough exterior but a kind heart, and her skills in tracking and fighting would be something Sebastian could respect.
Sebastian might fall for a young girl who was an outcast in society. She had a special gift of seeing demons. At first, Sebastian was only interested in her because of this unique ability. But as he spent more time with her, he started to care for her in a different way. He would secretly bring her little treats and protect her from other demons who might want to harm her. Eventually, his feelings grew into love as he realized how pure her heart was despite all the hardships she had faced.
In a love story with Sebastian, there would be a lot of power dynamics at play. Since he is powerful as a demon, his love interest might initially be intimidated. But as the story progresses, they could grow to understand each other. Sebastian might show his love in his own way, like protecting the person from other threats in the Black Butler universe, be it other demons or dangerous humans.
Writers often develop Sebastian's character by showing his internal struggle. Since pregnancy is not a normal state for a demon like him, he might struggle with new emotions and physical sensations. He could be confused about his role as a soon - to - be 'parent' while still trying to maintain his loyalty to Ciel.
In 'Black Butler', Sebastian and Ciel's relationship is complex. While there are strong emotional bonds and a deep sense of loyalty between them, it's not a typical romantic love. Sebastian is bound to Ciel by a contract, and his main goal is to consume Ciel's soul. However, their interactions often show a level of intimacy and dependence that can be misconstrued as romantic by some viewers.
Sebastian's character may develop a sense of humility. Usually, he is so self - assured and in control, but when sick, he has to rely on others, which can make him more understanding of human frailty. He might also become more introspective about his role as Ciel's butler and his own demonic nature.
A love story for Pluto might develop through shared experiences. For example, if there was a threat to the manor and Pluto and this potential love interest had to work together to protect it. During this time, Pluto could realize his deeper feelings for her. His loyalty to the manor and his newfound love could merge, making him even more determined to protect both.
In the Black Butler story, the moments where Sebastian shows his 'love' for Ciel in a somewhat romantic way are often intertwined with his duty from the contract. When Sebastian stands by Ciel during the ballroom dances, guiding him gracefully, it gives off a sense of a special bond between them. Also, the times when Sebastian defends Ciel's honor in front of other nobles can be seen as romantic. He doesn't let anyone slander Ciel and is always there to uphold his reputation. These actions, while not traditional romantic gestures, are quite significant in their relationship.