Two questions?

In Korea, foreigners can obtain different types of residence visas or registration certificates through marriage, relatives or qualifications. Among them, F4 visa is a permanent residence visa for Koreans or foreigners. F4 visa holders can freely enter and leave North Korea, and can work, do business and study.

As for the first question, as far as I know, in Korea, Han and Korean people can get a marriage immigrant visa, but the applicant needs to meet a series of conditions, including a real marriage relationship, a good relationship between husband and wife, and no criminal record.

As for your second question, as far as I know, Korean F4 visa is only for people with Korean nationality or permanent residence visa and their relatives, including children. Therefore, if a man holds an F4 visa and claims that it is because his father is Han and his mother is Korean, this situation may need further verification.

In a word, if you have more specific questions, I suggest that you consult relevant professional organizations or local legal advisers in order to obtain more accurate and comprehensive information.