I totally understand "Sinan Hate Club" (and a bit sympathize with it), but i would like to risk incurring some wrath.
Look around. War is everywhere. Countries make soldiers kill each other, for their own goals, and call it justice. But those goals do not even help those soldiers, as it all resolves around corruption and politics (eg. chapter about golden train).
And yet, war rages on, and nobody cares about all this killing.
So if politician can declare murder legal, for his own gain, why not dirty your hands, for something for yourself?
I'm not defending him, because he deserves death, but when soldier kills enemy in trench, we ignore it, as "it is war, and he had to do it, because other guy was from other country".
Let's look at the situation other way round:
Sinan is also a soldier and he fights and kills in this war. But only difference is that, he does not fight for Duchy, nor for Republic. He fights for "Sinan" and his battlefield is everywhere. He is a third side of this war, that others do not know about. Why should his deeds be condemned more, than actions of others?
And P.S.
I also hope, that he dies before he does something unforgivable to our MC. But he is also very interesting character, that deserves some reflection, not only hate.