THEORY/ SOMETHING I NOTICED

ok this is a very wholesome and cute manga i loved every moment of it! BUT!! there are some things in the manga I am questioning as to their true meaning and purpose of being there.
At the start, when the two were 'strangers' and sitting in Kazushi's room the TV was speaking about an un-caught suspect of a murder but it got cut out by Higaki becoming drunk and drousy. Later in the scene Higaki says things along the lines of "What if you were a murderer.... and im some wizard too???" Higaki's statement of being a wizard was his way of relating to his 'powers' which we later found to be real.
Which leaves room for the thought that the other half of his drunken babble could be a truth in an abstract way to to him or maybe even kazushi. So that poses the question "who is the "killer" and what did they "kill"?" First I thought a more direct meaning, about how possessive and opposite Kazushi acted around Higaki, exempting him from bullying as a child and acting happy around him and ONLY him, which lead my mind to wonder down more for lack of better words a "yandere' route (possibly killing the girl who broke up with higaki, and calling himself a stalker for repeatedly standing outside of higakis door ect). But, then i took a more metaphorical approach and i loved the way it worked for the story. I think the truth is that Higaki was (in a way) calling himself a murderer in the thought that he erased all memories of himself off Kazushi. Erasing himself was taking the other half of Kazushi's away which he knew could have been worse than death to them both. He was the "killer" or their childhood friendship but had "yet to be caught" because he believed Kazushi truly had forgotten. Anyway at this point im word spewing. I hope i didnt waste yall's time