Halo Wars | 1 Unit Type Challenge | Episode 3 (Spartans)

Welcome to the 1 unit challenge in Halo Wars I'm attempting to win a 1v1 against both a UNSC and Covenant legendary A.I using only 1 Unit type Is this even possible with every unit? I'm not sure but this is one of my all time favorite games and this is something I have always wanted to try. Enjoy