This is just an idea These could be viewed as Caydes personal weapons and the style he uses in combat. These are both sidearms but their unique perk allows to dual weild them when you get the pair. One sidearm is a primary One sidearm is a secondary You collect them from different quest lines or boss encounters. Once both equipped the Twin Eagles perk activates allowing them to both be active at the same time and dual wield. Twin Eagles allows Dual wield Slide at further distance Better accuracy while in the air Each weapon can have its individual perks of some kind and not sure what ... but im sure bungie or you guys can think of something. What you guys think? You like the idea of set items that activate when used together?