Bardroy's past might also be an obstacle. If he has some dark secrets from his pre - servant days, his love interest might be hesitant to fully commit. Also, in the world of Black Butler, there are always dangerous enemies around. His love might be put at risk because of his association with the Phantomhive family, as their enemies could target those close to the servants.
Well, imagine Bardroy meeting a girl in the town near the Phantomhive estate. She was selling flowers and he was out on an errand for the manor. He accidentally knocked over her flower stand. Instead of getting angry, she just laughed. He was immediately smitten. He started to visit her regularly, bringing her little treats from the manor's kitchen. They would talk about their dreams, his life as a servant and her hopes for her flower business. Their relationship grew deeper over time.
Another theme is his past as a soldier. Fanfictions like to expand on his military experiences, like how he dealt with the trauma of war. It could be about him having nightmares and how he overcomes them while serving the Phantomhives.
One great 'Black Butler Bardroy' fanfiction is 'Bardroy's Hidden Past'. It delves into his life before joining the Phantomhive household. It shows his struggle as a soldier and how those experiences shaped him into the person we see in the series. The story is full of action and some really emotional moments.
A love story with Pluto could center around his transformation. He was once a normal dog before becoming a demon. If he were to fall in love, it could be with someone who saw him both as the innocent dog and the powerful demon he became. This love could be a catalyst for him to question his place in the world of Black Butler, whether he should continue to serve his master blindly or follow his heart in the matters of love.
Well, perhaps the snake could be a shape - shifting demon in the Black Butler universe. It falls in love with a human character, maybe a maid in the Phantomhive household. They meet when the snake is slithering around the manor gardens and the maid shows kindness to it, not knowing its true form. Their love story could be full of secrecy and challenges as they try to navigate the complex world of demons and humans in the Black Butler world.
It could be Sebastian and Ciel. Their relationship in the original is very deep and complex. In a love story, the loyalty and protectiveness that Sebastian shows towards Ciel could easily be transformed into romantic love.
Perhaps when Undertaker and his love interest are dancing in a moonlit cemetery. The tombstones around them seem to be the silent witnesses of their love. The pale moonlight casts an otherworldly glow on them, and they forget about the dark and dangerous world around them for that brief moment.
It could be a dark and complex one. Claude is a demon, so his idea of love might be very different from a human's. He might view his love interest as a possession at first. Maybe he starts to feel something more genuine as he spends time with the person, but his demonic nature would constantly be at odds with his growing affection.
One possibility could be Sebastian Michaelis, the demon butler, as the snake in a transformed state falling in love with Ciel Phantomhive. It would be a very strange and complex relationship as Sebastian's loyalty is supposed to be to Ciel in a more master - servant way, but if he were a snake in love, it would completely change the dynamic.
One main obstacle is Jacob's prior feelings for Bella. His heart was so set on Bella for a long time that it made it difficult for him to fully recognize any potential feelings for Leah. Another obstacle is the nature of their werewolf pack. There are rules and dynamics within the pack that can sometimes get in the way of their relationship developing more freely.