Kira's downfall in the Death Note manga occurs when his identity is exposed and he's cornered by the forces opposing him. It's a combination of smart detective work and unforeseen circumstances. His fate is both tragic and inevitable given his actions.
A-Kira's story and Death Note might be linked in that they could exist in the same fictional universe, or A-Kira's actions could be a consequence of events related to Death Note. However, it all depends on how the story is crafted.
No. Harry Potter and Death Note are two completely different universes with their own distinct settings, themes, and characters. Harry Potter is a story about a young wizard in a magical world fighting against the dark wizard Voldemort, while Death Note is about a high - school student who gets a notebook that can kill people. Combining them in such a way as 'kira death note fanfiction' for Harry Potter seems inappropriate and forced.
It could be an interesting experiment, but it would be extremely challenging to pull off successfully. Firstly, the magic system in Harry Potter is very different from the power of the Death Note. In Harry Potter, magic is something that can be learned and controlled to some extent, while the Death Note is a very specific and deadly tool. Secondly, the moral and ethical landscapes of the two stories are distinct. Harry Potter has a more black - and - white view of good and evil in many ways, while Death Note is all about moral gray areas. Combining them would require a great deal of creativity to make it work without completely ruining the essence of either story. However, most likely, it would end up being a rather odd and disjointed piece of writing.
Ryuk would probably just be amused. He is a Shinigami who has seen a lot in his existence. Fanfiction is just another strange human creation to him. He might chuckle at some of the more outlandish ideas in the fanfictions, like a character having superpowers beyond the Death Note.
Misa would likely be excited. She is a big fan of Light and the whole 'Kira' concept. In fanfiction, if there are scenarios where she has more power or a closer relationship with Light, she would be all for it. However, she might also get jealous if there are other female characters getting too close to Light in the fanfictions.