I would consider Arsat a tragic character.  On one hand, Arsat is tragic because at a critical moment, he is faced with equally desirable, but ultimately incompatible courses of action.  At the most essential instant of his life, Arsat is faced with defending his brother and the honor that goes along with it or lose the women he loves.  Both are desirable, and the choice is constructed in a manner where only one can be chosen.  Both cannot be had at this instant.  It seems that either choice made is one out of sadness.  Arsat will be miserable with either choice.  The reality is that his tragedy lies in having to choose, but facing agony regardless of it.  The indication that Arsat is not complete when he ie with Diamelen is reflective of the agonizing level of choice and the pain that was intrinsic to such a choice.  It is here where I think that Arsat is a tragic character.  It is inconceivable to see if anyone else would want to be in such a position and in reflecting to this point, I think that tragedy becomes evident.  One does not envy Arsat because one does not envy the choice he had to make, one in which tragedy is evident.  The nothingness that is reflected when Diamelen dies helps to only enhance such a tragic condition.