To get the deathsingers' cards: 1. load up the mission where you go invisible to steal some of crotas essence. 2. Turn your volume down (doesn't have to be muted but just low) 3. when u reach the area with the black pool (just before you reach the deathsingers) stand in it and shoot at them both until they're dead. Your cloaking won't be broken and your ammo will refill if you run out 4. Profit [spoiler]#2 isn't a requirement, the deathsingers let off a really loud scream when u kill them[/spoiler]