In these verses, the angel explains to Daniel the symbolic meaning of the things he saw in his vision. The animals and horns actually represent human rulers and kingdoms. (See: [[rc://en/ta/man/translate/writing-symlanguage]])
Possible meanings are 1) this refers to the kings of Media and Persia or 2) this is a metonym in which the kings represents the kingdoms of Media and Persia. AT: "the kingdoms of Media and Persia" (See: [[rc://en/ta/man/translate/figs-metonymy]])