questions:
1. How has Misa forgotten about the death note but not about Light despite her whole interactions with him happening only because of the death note
2. How and with what were the empty spots of Misa's memory replaced with now that she forgot about the death note?
3. After forgetting about the death note how can Light remember anything about the Kira case despite his whole reason of even being involved with it is because of the death note?
4. With what were the memories of the death note replaced
5. How can light still think he's Kira of he's forgotten about the death note?
Answers:
1. Why Misa forgot the notebook but remembered Light:
The memory gaps left by the death note were naturally replaced by the brain based on the remaining broken bits of information of light that weren't related to Light having the death note.
2. How Misa's empty memory spots were replaced:
Same as ans1. The brain replaced the gaps left over from the death note by making conclusions based on broken memory fragments that were unrelated to the death note.
3. How Light remembers the Kira case after forfeiting ownership:
Because his work on the task force was public, deductive, and didn't require "shinigami magic" to remember, his brain retained it. He simply viewed the case from the perspective of an incredibly brilliant, innocent college student helping the police.
4. With what were Light's memories replaced?
Like Misa, Light’s brain adjusted his memories to maintain logical consistency.
5. How can Light still think he's Kira if he forgot the Death Note?
He doesn't think he's kira. As of now light fully believes he's an innocent man wrongfully accused by L and is here to clear his name.
Just some info that might help out some new watchers