In many fanfictions about Light Yagami and Misa, their relationship is often complex. Light initially uses Misa for his own ends in the 'Death Note' story. He manipulates her feelings because of her Shinigami eyes which are useful for his plan to create a new world. Misa, on the other hand, is blindly in love with Light. In fanfiction, this dynamic can be explored in different ways. Some might show Misa slowly realizing she's being used, while others may focus on a more 'romanticized' version of their relationship where Light actually develops some real feelings for Misa.
I'm not sure specifically which 'Kazuma Yagami' in a light novel as the name is not widely known in extremely popular mainstream light novels. It could be a character from a relatively niche or new light novel series.
There are a vast number of fanfics on the internet, and given the creativity of the fan community, it's very possible that there are fanfics portraying Light Yagami as gay. Fanfic writers often take characters from their favorite shows or books and put them in new and different situations, including changing their sexual orientation to tell a different kind of story. These fanfics can range from being well - written and thought - provoking to just being a bit of fun and experimentation. So, if you look hard enough on the right fanfic websites, you may come across one.
Light Yagami's death in the manga occurs because Ryuk, the shinigami who gave him the Death Note, decides to end his life. It's a result of Light's descent into madness and his attempts to evade justice.
Another theme is the re - imagining of relationships. In the original story, Light has certain relationships with characters like L and Misa. In the fanfics with a female Light, these relationships are often re - evaluated. Maybe female Light has a more complex relationship with L as they try to outwit each other, and her relationship with Misa could be more of a sisterly rivalry or a different form of alliance.
One unique aspect is the clash of different moral systems. For example, when Light crosses into a universe like 'Star Trek' where the Federation has a very different view on life and justice. His use of the Death Note would be highly controversial. Another aspect is the exploration of his character in new settings. In a crossover with 'Fullmetal Alchemist', he would be exposed to a world full of alchemy and different power structures.
Some fanfictions might depict a scenario where Light and Dark Yagami exist in parallel universes and somehow interact. For example, Light from one universe might meet Dark Yagami from another and they have to come to terms with their differences. There could also be a fanfiction that focuses on the psychological aspect of Dark Yagami's actions. It could analyze his motives and how his actions affected those around him in a more in - depth way compared to the original story. Additionally, a fanfiction could explore a world where Dark Yagami's actions have different consequences, leading to a completely different story arc for all the characters involved.
Maybe Misa. She's completely devoted to Light, but what if she discovers that Light has been using her all along? In a fit of rage and heartbreak, she could kidnap him. She has the means as she's also involved with the Death Note. She might want to make Light pay for his betrayal or force him to love her truly.
A frequent theme is the exploration of what would happen if the power of the Death Note was introduced to the Naruto universe. It could disrupt the balance of power that exists in Naruto's world. Also, the theme of identity can be seen as Light Yagami has to adapt to a new world and its rules while still being himself.