Rules: the battle takes place in a single star system, the system can not be wiped out (sorry Halo Rings). But feel free to blow up or glass planets. For the sake of having a somewhat fair battle no omnipotent beings are invited, precursors counts as omnipotent beings in this case. When it comes to the flood they might be able to infect the Orks (I'm uncertain of this because they are half plant). But the flood CAN'T infect Tyranids as they are not sentient life. NO COMBINING TECH e.g you can't have a spartan with forerunner armour. *Important* Some of you may bring the covenants plasma weapons into account, before doing this you have to realise the difference between Warhammer 40k and Halo plasma weapons. http://warhammer40k.wikia.com/wiki/Warhammer_40k_Wiki http://halo.wikia.com/wiki/Main_Page links provided for fact checking.