I think the answer to your profound question Zyltan is that it is a fine line.
Ones mans justice is the cause for another mans Vengeance. An example if you will (And just an example before anyone leaps on me about it.)
If Threap decides to strip a young Mercinaen for a slight against him, be it word or deed, He is extracting his own perceived Justice for the slight.
If Dunccan were to retaliate and perform the same act on another Thakrian young person, that would be Justice in Dunccan's eyes, yet vengeance in mine.
Justice and Vengeance are closely entwined, where you stand on the matter, I personally believe is a matter of your own perception and beliefs. My own belief states that there is no concept of justice, merely a never ending circle of Vengeance that ultimatly is the source of power for my Ladies realm. I'm sure the followers of Lord Castigere would feel somewhat differently.
Regards, Father Cimares.
Written by my hand on the 12th of Ilmarael, in the year 1120.