Remembering a spongebob squarepants episode...
Spoiler for Kinzo´s death:
What about if kinzo is a robot?
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If in higurashi there was a new disease ( hinamizawa syndrome ) and the drug that caused it, think some, nanjo is a doctor so what about if he discovered the way of making people "robots" after death with a drug? if he did, he wouldnt have done that alone, ir OKONOGI exists, he would have contacted takano (yes i know, this is a very great crossover with higurashi) and she with her awesome medical skills would have created the drug.
Nanjo wouldnt have neccesarly did it, Eva or Rudolf could because both have connections to okonogi. Rudolf has a bigger chance because he almost always dies at the first twilight and he would be the " takano/tomitake" of umineko. But due to both of them being " poor "compared to takano, they maybe have hallucinations of Beatrice as Takano with Oyashiro-sama and they grown empathy together.
Congratulations for ryukishi support!