This verse is parenthetical, to tell us what the angelic speaker had done two years previously (426 B.C.)
Darius the Mede is the same king as in Daniel 9:1, i.e. Cyrus.
stood. was at my station.
him: i.e. Michael.
Related Commentaries of Daniel 11:1
Daniel 11:1
1 Also I in the first year of Darius the Mede, even I, stood to confirm and to strengthen him.