I think AC 4 should be set in the Egyptian Era . I you look up Ancient Egyptian Swords there are daggers, swords, throwing knives, everything. In AC 2 there are tombs in which you complete to unlock Altair's armor but you could replace tombs and romulus tombs with pyramids. The main story line could be about an ancestor of Desmond a poor peasant parents are killed by a corrupt pharaohs men. So when he gets older he hunts the pharaoh and kills him.