One common theme is the rivalry - turned - into - attraction. Since Natsu and Gray are rivals in the original Fairy Tail series, in the lemon fanfics, this rivalry can often be a starting point for their relationship to develop into something more passionate.
Well, in these fanfictions, a common theme is the transformation of their friendship. They go from being just comrades in Fairy Tail to having a more sensual and passionate connection. Another theme could be the struggle with their identities. Natsu is a dragon slayer and Gray is an ice - make wizard, and their powers can sometimes be in conflict or in harmony with their relationship. And of course, the theme of love and lust is quite prevalent, as it is in most lemon fanfictions.
Often, in these types of fanfics, the theme of loyalty might be prominent. Natsu, as a werewolf, might have to deal with issues of loyalty to his friends or his werewolf pack (if there is one in the fanfic). Also, the struggle between his human and werewolf sides could be a major theme. For instance, his human side might have certain values, while his werewolf side has different instincts, and the fanfic could explore how he balances these two aspects. This can make for a very interesting character - study - like story.
Another common theme could be the exploration of their individual personalities within the context of their relationship. For example, how Natsu's fiery nature and Sorano's own traits interact and complement each other. It could also involve themes of loyalty and friendship, as their relationship might be built on a foundation of mutual trust and support, which then blossoms into something more romantic as the fanfic progresses.
Romance is also a big theme. Many fanfictions play around with the idea of a romantic relationship between female Natsu and Gray. They might have some cute moments like blushing or secretly caring for each other.
A frequent theme is the exploration of their past traumas and how they help each other heal. Natsu has his issues with being abandoned as a child, and Gray has his own demons related to his family. In the yaoi fanfics, they often rely on each other for emotional support. This not only strengthens their bond but also makes the relationship more believable and deep. Additionally, the power dynamics between their magic abilities play a role, with them sometimes using their powers in unique ways during intimate or emotional moments.
Love and attraction are common themes. Since it's a ship - focused fanfic, the relationship between Erza and Gray is at the center. Another theme could be conflict, like internal conflict within themselves about their feelings or external conflict that tests their relationship.
Well, another place could be some dedicated anime or Fairy Tail fan communities. Sometimes, fans share their fanfics in those groups. For example, on Reddit, there are specific subreddits for Fairy Tail where people might post or recommend Natsu and Gray lemon fanfics. But make sure to follow the community rules.
Often, there's the theme of loyalty in these fanfictions. Their loyalty to each other, which was present in the original Fairy Tail series as friendship - based loyalty, gets intensified in a romantic context. They are loyal to each other not just as comrades but as lovers. There can also be the theme of overcoming obstacles, like dealing with the reactions of their friends or guildmates who might not understand their relationship at first.
The popularity of Natsu x Gray lemon fanfics may also stem from the fact that the Fairy Tail fandom is quite large and diverse. There are fans who enjoy different types of fan - created content, and lemon fanfics are one such category. For some, it's about seeing their favorite characters in a different light, with a more intense emotional and physical connection. Additionally, the shared adventures and history between Natsu and Gray in the original series provide a rich backdrop for fanfic writers to build on when creating these types of stories.
Adventure is also a big theme. They usually go on some sort of journey or mission. This could be a quest to find a lost magical item or to defeat a powerful enemy. It gives the story a lot of action and excitement.