One common theme is the clash of different worlds. Byakuya is from a very structured and traditional world in 'Bleach', while the OC often comes from a different background, so exploring how they interact and adapt to each other's worlds is a big part of many fanfictions.
Love and redemption are also popular themes. The OC might be a character who helps Byakuya to overcome some of his past traumas or cold - heartedness. For example, the OC's kindness and understanding could gradually thaw Byakuya's icy exterior, leading to a love story that is also about his personal growth.
Power and responsibility is another theme. The OC may have unique powers, and together with Byakuya, they have to face challenges that require them to use their powers responsibly. This theme often leads to interesting plotlines where they have to make difficult decisions and learn from their mistakes.
Power and status also play a role. Since Byakuya is from a noble family in the Bleach universe, the OC may have to navigate the power dynamics. Sometimes, the OC has their own unique power that either challenges or complements Byakuya's.
One common theme is the clash of different worlds. Since Byakuya is from a noble family in the Soul Society and the OC is often an outsider, there's the theme of how they bridge that gap. For example, in many fics, the OC has to learn the strict rules and traditions of Byakuya's world while also making him see things from a different perspective.
One common theme is the exploration of different cultures. Since Byakuya is from a specific fictional world, when he crosses over, there's a chance to compare and contrast different settings and ways of life.
One common theme is power and leadership. Since Byakuya is a powerful character in the original Bleach series, in the fanfictions with a female version, she is often depicted as a strong leader. Another theme could be relationships, whether it's her family relationships or romantic ones. For example, how she interacts with her sister in a different light as a female character.
One common theme is the exploration of Byakuya's reserved nature. Since he is a very stoic character in the original series, fanfics often focus on how the reader can break through that exterior. For example, in many fics, the reader is shown to be the one who can make Byakuya show his more vulnerable side.
Isolation is also a theme. Byakuya is often portrayed as a rather aloof character. So in love story fanfictions, his journey from isolation to opening up to love is a common plotline. For example, he might start off pushing away the person he has feelings for due to his solitary nature, but then gradually let them in.
Another interesting one is 'Beyond the Boundaries'. Here, the OC is from a different realm entirely. When she meets Byakuya, it sets off a chain of events that challenges both of their beliefs. The author does a wonderful job of creating a vivid world and making the relationship between the two characters feel real and engaging.
There's also 'The Unseen Path'. In this fanfiction, the OC is a healer who catches Byakuya's attention during a battle. The story delves into their growing relationship as they face various challenges together in the world of Bleach. It's really interesting as it shows a different side of Byakuya.
Another characteristic often explored in fanfiction is his power. His swordsmanship and his zanpakuto's abilities are sometimes elaborated on in ways that go beyond what was shown in the original anime or manga. Fanfic writers might create new battles or training scenarios for Byakuya to show off his strength and skill, while also delving into how his power affects his relationships with others, either through envy, respect, or fear.
Well, 'Young Byakuya: The Making of a Noble' is a fascinating fanfiction. It shows how his noble upbringing influenced his early life and decisions. It also includes his interactions with his family members. Additionally, 'Byakuya's Youthful Encounters' is worth reading. It tells stories of his unexpected meetings and how they shaped his view of the world around him during his younger years.