They do battle on red faction Mars back when you could live on the surface. No orbital support and no titans bigger then Reaver Titans because titans. this is the Empires 501st. the 501st get Darth Vader. If curb stomp in Mordian Iron Guards favor the 501st get The Coruscant Guard, star killer and the battle field becomes Coruscant. And if its still a curb stomp and i am just really stupid then i am sorry.
the 501st start in the yellow area the Mordian Iron Guards start in the blue and here is a link to a map http://www.neoseeker.com/resourcelink.html?rlid=193363