Its obviously star wars since the fact that they have possibly the most badass characters while halo just has the masterchief and the elite but if anything they would betray the masterchief to join the dark side with Darth Vader because...he's Darth Vader! WHO WOULDN'T WANT TO FIGHT WITH VADER!!?(other than Luke) But I will admit that they would each put up a decent fight that I would love to see!