Halo, because, assuming we are only talking about canon universe things, then Star Wars can only use what is within the movies, but Halo can use everything across all the books, games, and everything else. Therefore, Halo would win due to the flood mass-infecting entire populations of species, the UNSC and the Covenant destroying everything else as they see fit, and THE GIANT HALO RINGS THAT CAN LITERALLY KILL ALL LIFE FORMS IN THE UNIVERSE.