How about a space frontier styled RPG.
You have two playable major factions, the "terran" faction is a bunch of human colonies (dictatorship, explorers, rebels,etc...) they have your usual guns and SPESS armor, the "protoss" are the super mega advanced natives with laser swords and stuff.
The third unplayable faction is the "Zerg" faction, with hives scatered across the planet.
The point of the RPG is for one race to prevail over the other (Humans genociding the "Protoss" because they wont leave their temples and stuff, "Protoss" forcing the humans to leave) with hive raids in which the "Terran" and the "Protoss" race trough the "zerg" hordes to get to loot and stuff.
Also the "" are for race/faction stereotype.