Shin Malphur, he created a group of wanna be dredgens, his greatest enemy, so he could keep a close eye on them. Drifter was/is one of them. When the Dredgens go bad and follow the darkness, Shin hunts them down and kills them, as he did with Callum Sol. Drifter says he acts like he owns the Golden Gun, even though all hunters have acess to it. The purpose of Malfeseance is that Drifter wanted to create a bunch of this weapons, because they can kill him for good.
English
-
off topic but i don't think callum is dead. after finishing the quest we are lead to believe that but if you read the lore carefully, shin and callum staged everything to scare other dredgens. read on destinypedia. basically callum finds a dead ghost and used it as a recording device somehow. shin gg'd callum but he was able to be rez'd.
-
The means by which it's meant to kill Shin Malphur is not the Taken damage boost, it's the exploding shot. Drifter's logic is that Shin only needs one shot to kill them, but he can't outshoot everyone at once. If he hands out Malfeasance to other people and it comes to a standoff, everyone can shoot Shin at once and the shots will explode. "And all of us, with this in hand? Even the Man with the Golden Gun should have pause. Maybe we can't out-shoot him. Maybe he can't be out-shot. But if we all take our shot together? We don't have to beat him to it. He'll die, too."