Where does “Yomi” come from?

Yomi (English) comes from Japanese 黄泉, from Middle Chinese 黃泉.

Ancestry of “Yomi”, step by step

Step	Language	Word	Meaning
1	Japanese	黄泉	the land of the dead; the afterworld, underworld;...
2	Middle Chinese	黃泉	—

Yomi — Etymology, Origin & Word History | Etymology Explorer