You have an assignment. You’ll do anything for the assignment. Partly because you’re part of the union and the other thing is that they’ll kill you if you don’t do it . So what’s the assignment? To get information on Baku and his friends so that the union can kill them . The union wants to kill Baku and his friends simply because of some “ war “ that’s been going on between the union ( 10 members ) and Baku and his friends ( 5 of them ) . It eventually became something much more than a war when Baku was accused of killing Baekjins ( leader of union ) brother . He was framed .. it was actually a stupid accident that Baku had to stumble across at the wrong time .