One main theme is loyalty. Given their characters, the exploration of whether they are truly loyal to each other or have their own hidden agendas is often a key part. For example, in many fanfics, Kisaki's manipulative nature might put their loyalty to the test.
No. Harry Potter is a completely independent and original fictional universe created by J.K. Rowling. It has its own unique storylines, characters, magic systems, and world - building elements that have no relation to a 'Draken fanfiction'. The Harry Potter series is about a young wizard's journey through Hogwarts School of Witchcraft and Wizardry, facing dark magic and growing up, which is very different from what a fanfiction would be.
As of the current chapters, Draken is still alive. The storylines haven't led to his death. The character has played an important role and continues to be part of the ongoing narrative.
There's also 'The Unlikely Alliance'. In this fanfic, Kisaki and Hanma find themselves in a situation where they have to work together against a common enemy. It shows a different side of their relationship, with some interesting plot twists.
One possible plot could be that Harry discovers Draken through some magical means in the wizarding world. Maybe a spell goes wrong and he gets a vision of Draken's world and becomes intrigued. Then he starts to study about Draken secretly, against the rules of the wizarding society.