One common theme could be friendship evolving into something deeper. Since Ace and Luffy have a strong bond in the original 'One Piece' story, in these fanfics, it might be explored as a more romantic or intimate relationship. Another theme could be sacrifice, as both characters are known for their selfless natures in the anime.
I'm not an expert in this particular type of fanfic. However, you could also join some 'One Piece' fan communities on social media platforms or forums. Fans there often share and discuss their favorite fanfics, including those with Ace and Luffy in a certain relationship. They might be able to point you to some great reads.
One popular 'luffy x ace yaoi fanfic' is 'Bond of Brothers'. It really delves deep into their relationship, showing how their bond could be interpreted in a more romantic light. The story has some great emotional moments that draw readers in.
One common theme is the strong emotional bond between Ace and Luffy. It often explores their relationship in a more romantic or deep - seated way compared to their canon friendship. Another theme could be adventure, as they are both characters from One Piece, so the fanfics may incorporate the elements of their pirate adventures while also delving into their relationship.
A common theme is also the exploration of their physical attraction. Writers might describe how they notice each other's bodies in a different way than just the normal brotherly concern. For instance, Ace might be captivated by Luffy's carefree nature and how it's reflected in his movements and expressions, which then leads to a physical attraction. This can be a starting point for a more in - depth romantic relationship in the fanfiction. There could also be themes around jealousy, like if another character shows interest in Luffy, Ace would feel jealous in a romantic way.
I'm sorry, but I don't have specific ace x luffy yaoi fanfic to recommend directly. You can try searching on some popular fanfic websites like Archive of Our Own (AO3). There are likely many fan-created works there related to this pairing.
Adventure is also common. They are pirates after all. Fanfictions might take them on new quests or have them explore uncharted islands together, much like in the original series. For example, they could be searching for a hidden treasure that has a special meaning to their family. It's a way to continue the spirit of adventure that One Piece is known for in a new context.
The popularity also stems from the fact that there are so many unexplored aspects of their relationship in the official story. Fanfiction allows writers to fill in those gaps and create stories that satisfy the fans' curiosity. For example, their early days together or how they would interact in different settings.
For some, it's the unique take on their relationship. Luffy and Ace have a very strong bond in the original story. In yaoi fanfics, it takes that bond to a different level, exploring a romantic side that can be quite exciting for fans who like to see different interpretations of their favorite characters.
You can start by looking on some well - known fanfiction websites such as Archive of Our Own (AO3). It has a large collection of One Piece fanfictions, and you can use the search function to specifically look for Ace x Luffy yaoi stories. There are usually tags and filters that can help you narrow down your search to find the ones that suit your taste. Another option is Fanfiction.net, which also has a good number of One Piece fan works, although the tagging system might be a bit less refined compared to AO3.