This manga is the best. Also, further proof to my idea that Ooki is just some weird observer outside our earthly realm, considering the last few chaps where she's actually been helping our boi thru yandere's antics
While I don't have an issue with the forgotten childhood friend trope, I know some people do. In this case though, I think it is more justified than usual though since it gives Paperbag-kun a reason to be following her rather than just stalking her out of the blue
@ilikeanime + others who all ask the same question - yes, remember the text on the last page of last chapter - "As long as our "hearts" come together, we can find the answer we're looking for... and then their bodies came together too!"