A common theme could be friendship. Since they are both interesting characters from the same universe, many fanfictions might explore how they become friends despite their differences.
One place to start looking for 'female Natsu and Cobra fanfiction' could be fanfiction.net. They have a large collection of various fanfictions. You can search for tags related to 'female Natsu' and 'Cobra' to narrow down the results.
She might become angry at first. Natsu is known for her fiery temper. So, she could lash out at the person who betrayed her, confronting them directly and demanding an explanation.
Another idea for this fanfiction could be that they were both students at a very old and secret magic academy in the past. Zeref was an outcast because of her dark magic, but Natsu didn't care. He befriended her, and together they explored the secrets of the academy and the magic within it. However, their friendship was soon tested when the academy's elders discovered Zeref's true nature.
I'm not sure who exactly Natsu is just from 'natsu reads fanfiction'. It could be a normal person who just enjoys reading fan - made stories. Maybe it's a nickname for someone within a particular fan community.
Their relationship could develop through shared battles. When they fight side by side against common enemies, they start to trust each other. For instance, in a fight against a group of dark mages, Natsu and the female demon realize that they complement each other's fighting styles. Natsu's brute force combined with the female demon's more strategic and stealthy attacks make them a powerful duo.
In this fanfiction, the relationship between Harry Potter and the cobra could be based on mutual understanding. The cobra might see Harry as someone different from other wizards, and Harry could be intrigued by the cobra's mystery. For example, the cobra could have a connection to an ancient magic that Harry needs to uncover in order to defeat a new dark force.
One possible idea for a fanfiction could be a story where Kinana and Cobra meet again after a long time. Maybe Kinana has developed new powers and Cobra is on a path of redemption. Their encounter could be filled with tension as they remember their past interactions, both good and bad.
A common theme could be friendship. Natsu and Gajeel have a complex relationship in the original series, and in fanfictions with a female Gajeel, exploring how she fits into that friendship dynamic can be interesting.
One common theme is friendship. They often start as just acquaintances or even rivals and then develop a deep friendship. Another theme is growth. Both characters, especially female Natsu, grow in terms of their powers and personalities. For example, in many fanfictions, female Natsu learns to control her new - found abilities better with Laxus' help.