>>17944005
They are through and through Korean. They hailed from the Korean States of Jin and Wa and even Gojoseon, many of them speaking both Korean and Japonic which is why early records in Yayoi period Japan were written in Korean and the ruling class also documented much in Korean while commoners mainly spoke the Japonic language.

Looking at the Yayoi archeological records and artifacts even show ties to Korean culture from the Peninsula. There is a reason why Korea has a huge impact on Japanese culture from the Yayoi period, they were both genetically & culturally thus ethnically Korean.