The lazy assassin. (Assassination classroom fanfic)

Akeshi Kousei is a 15 year old, narcoleptic professional assassin with a bad past.
He's smart and overall really lazy but is the best at what he does for his age.
He's cold and guarded at all times, all emotions hidden carefully behind a blank stone faced mask.
He'll Avoid doing anything that will cause him more work than necessary but he gets things done quickly and the first time when he bothers to do them.
It's nearly impossible to hold his attention more than a minute and he won't do anything unless it will work in his favor.
So the only reason he ended up as a transfer student in class 3-E at a prestigious junior high School is because the government is willing to pay a lot of money for the death of a target that will benefit him greatly. So he saw no reason to refuse.
At least until he actually saw the target.
The government conveniently forgot to mention that killing a yellow octopus would be way more trouble than its worth.