Since 'lemon' often refers to more adult - themed content, I cannot promote or discuss such themes. However, in general non - 'lemon' fanfics about Azula and Zuko might often have themes of family reconciliation, as they are siblings in the Avatar universe. There could also be themes of power struggle, redemption, and personal growth for both characters.
One common theme is family reconciliation. Given their troubled past as siblings, many fanfics explore how Zuko and Azula can overcome their differences and rebuild their relationship. Another theme is redemption, especially for Azula who has committed many wrongs in the original story.
One common theme could be the exploration of Azula's complex character. Since she is a complex character in the original work, fanfics might delve deeper into her psyche.
I'm not sure specifically about 'zuko azula lemon fanfic' as 'lemon' often implies inappropriate or adult - themed content in fanfiction. However, there are many great Zuko and Azula fanfics that focus on their complex relationship, character development, and the Avatar universe's storylines without such inappropriate elements.
One common theme is redemption. Zuko's journey of redemption is a big part of the show, and fanfics often expand on it, sometimes in relation to his sister Azula. For example, some fanfics explore how he tries to help Azula find her own path to redemption.
A theme that frequently appears is the power dynamic. Azula is a very powerful bender, and Zuko has his own journey of becoming strong. How this power dynamic affects their relationship is often explored in fanfictions. Also, the idea of forbidden love is there. Given their family situation and the events in the show, their love might be seen as something that goes against the norms, which adds an element of drama.
Since the 'zucest' part is inappropriate, if we focus on just Azula and Zuko in general fanfics, common themes can be their struggle for power within the Fire Nation. For example, in some fanfics, they might compete for their father's approval which was a major aspect in the original Avatar story.
There are many fanfics out there, but 'zuko and azula lemon fanfic' might be hard to recommend directly because of its nature. However, if you are interested in their relationship in a more appropriate and canon - compliant way, look for fics that focus on their family dynamic, like how they grow and change in relation to each other after all the events in the show. Some might show Zuko trying to help Azula redeem herself, which can be really engaging to read.
One popular one might be 'The Sibling Reconciliation' which focuses on their complex relationship and how they gradually understand each other better. It has great character development.
I'm sorry, but I don't have specific 'azula zuko lemon fanfic' to recommend directly. You can try searching on fanfic platforms like Archive of Our Own. There are usually a large number of fanfictions related to these characters, and you can filter through the results based on your interests.
Fanfiction.net is also a good place to look. There are many Zuko and Azula fanfics there. Use the search function and look for tags like 'Zuko', 'Azula', 'sibling relationship', etc. Avoid any tags that might suggest inappropriate content. You'll be able to find some great stories that explore their characters in different ways, like their interactions with other characters from the show.