Often, the theme of sacrifice is present. In the Naruto universe, characters are often willing to sacrifice for their loved ones. In 'obito rin lemon fanfic', this could be explored in more depth, especially in situations where their love is put to the test. Also, the theme of second chances might be common. Maybe they missed an opportunity to be together in the original story, and the fanfic gives them a second chance to explore their relationship, whether it's a romantic or a more platonic bond.
One common theme could be unrequited love. Given the complex relationship between Obito and Rin in the original Naruto story, fanfics might explore the idea of one of them having feelings that the other doesn't initially recognize. Another theme could be redemption. Obito has a rather dark past in the series, and fanfics might show how his relationship with Rin could be part of his journey towards redemption.
Another common theme is the exploration of their past relationship. Fanfics often go back to their childhood days and show how their feelings for each other started. This gives readers a deeper understanding of why they are so important to each other.
Long - lost love is also a popular theme. Sometimes, due to various circumstances in the Naruto universe, they are separated, and the fanfictions focus on how their love endures over time and distance. Also, the theme of unrequited love can be explored, where one might think the other doesn't feel the same way at first, but then the story unfolds to show otherwise.
I'm not sure which specific 'obito rin lemon fanfic' are considered good as I don't have a comprehensive list at hand. However, you can try looking on fanfic websites like FanFiction.net or Archive of Our Own. Search for relevant tags such as 'Obito', 'Rin' and browse through the results to find ones that seem interesting to you.
Since Obito has a complex backstory in Naruto and Sakura is also a well - developed character, in 'Obito and Sakura' fanfiction, themes might revolve around redemption. Maybe Obito trying to find a new path in life with Sakura's help and love. And of course, there could be themes related to the power of love in changing a person, which could be explored in a more 'romantic' or 'intense' way in lemon fanfictions, but that's just speculation.
A major theme is the power of forgiveness. Naruto is all about forgiving others, and when it comes to Obito, this theme is often explored. How can Naruto forgive Obito for all the harm he has caused? Also, the theme of changing one's fate. Obito's fate seems set in the original story, but in fanfics, he often tries to change it with Naruto's influence. There are also themes related to the understanding of different ideologies as Naruto and Obito have very different outlooks at times.
I'm not sure specifically about 'lemon' fanfictions as they often involve inappropriate content. However, there are many great fanfictions about Obito and Rin that focus on their relationship in a more positive and appropriate way. You can try searching on fanfiction platforms like Archive of Our Own and filter for works that are rated for general audiences.
One common theme is growth. Rin's growth from a child to a young woman and how that affects her relationship with Sesshomaru. Another theme is protection. Sesshomaru's role in protecting Rin is often a central focus.
The theme of discovery is also popular. Naruto might discover something new about the past through Rin, or Rin could discover the new world that Naruto is a part of. For example, she could learn about all the new ninja techniques and the changed political situation in the shinobi world. It makes for an interesting exploration of the Naruto universe from her perspective.
Adventure is also quite common. They are usually sent on some sort of journey or mission which tests their abilities and their bond. For example, they could be exploring a mysterious forest or an ancient ruin. During this process, their characters are further developed.
One frequent theme in 'Obito x OC fanfic' is the exploration of power and how it affects relationships. The OC might have unique powers or abilities that interact with Obito's. For example, if the OC has a power related to time - travel, it can create an interesting dynamic with Obito's own powers. Also, the theme of loyalty is often explored. As Obito has had issues with loyalty in the original story, the fic might show how the OC helps him regain his sense of loyalty or how they are loyal to each other in difficult situations. It can be really engaging to see how these themes play out in different fics.