Where does “あの世” come from?

あの世 (Japanese) comes from Japanese 世, from Middle Chinese 世.

あの世 (Japanese): the world of the dead; the otherworld

Definitions

  1. the world of the dead; the otherworld

Ancestry of “あの世”, step by step

あの世 traces back through two separate lines of ancestry.

via Japanese

StepLanguageWordMeaning
1Japaneseworld, society; this world, this life;...
2Middle Chinese

via Japanese あの

StepLanguageWordMeaning
1Japaneseあのsimilar to English er or umm, said when hesitating in speech
Every word from Middle Chinese Every word from Japanese
あの世 — Etymology, Origin & Word History | Etymology Explorer