From Destinypedia, the Destiny wiki
In battle, Marauder assassins will attempt to use their cloak technology, concealing themselves from sight and the radar as they attempt to kill their enemies with bursts of shrapnel from their Shrapnel Launcher, dealing serious damage at medium range. Up close, they will attempt to melee with their wrist-mounted blades, which can bring down Guardian shields rather quickly. They are also quick on the move, using their arms and legs to scurry on the floor. This makes them hard to hit due to their erratic motions and low profile. However, like most Fallen troops, they are physically frail and can be taken out with any form of weaponry.
List of appearances