Whose apprentice is Huo Ying Namikaze Minato?

Namikaze Minato is an apprentice of Jiraiya, one of the three forbearance, and Jiraiya's teacher is Sarutobi Hiruzen, the third generation descendant of Muhuoying. The apprentices of Watergate were Hatake Kakashi and Uchiha Obito, and one of them seemed to be Chun Yelin. . . . . What? What forest? I can't remember this clearly. . He died shortly after he appeared. .