A Deal With the Devil

"What makes you think that letting a killer out of his cell and giving him a gun, which he could easily shoot you with, is a good idea?"
"It's not a good idea; I'm all out of those. That's why I'm here."
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Eren Jaeger is a member of the Scouting Regiment Special agency. Being one of the top 20 who were first-appointed into the organization, he has lots of respect and is just under the position of the commander's right-hand man. He idolizes his boss and hardly ever questions his judgment, leading them to truly trust one another.
However, they now face a great threat that none of them are ready for. A dangerous gang's boss's plan has just been hinted at, that could kill an unknown amount of people and alter their lives as they know it. Their response they craft must be done with the utmost concern, coordination, and caution, or it's all over.
Whilst coming up with a plan, Eren remembers not too long ago when they arrested a certain man, and his friends, who knew exactly how to handle killing targets and doing it without suspicion. Eren hasn't only idolized his boss's great organization and planning, but also his seeming gambling addiction. And that's ultimately what leads the young man to stand in front of a trained killer and ask him for help.