https://www.gamespot.com/articles/destiny-2-big-changes-in-store-for-two-well-known-/1100-6457816/

Bungie has been steadily updating Destiny 2 with a variety of big changes; most recently, it added unique Nightfall rewards to the game and made some broader weapon changes. It also has several more updates in the works including an overhaul to some Exotic weapons. Today, Bungie revealed some of the tweaks it has in store for a particular pair of weapons.

Sturm and Drang are two guns that actually have complementary perks. In other words, they work best when carried together. Drang, a Legendary Sidearm, will reload Sturm, an Exotic Hand Cannon, on kills and will overload it above its magazine capacity upon consecutive kills. Sturm, meanwhile, also reloads Drang upon kills.