What is God's ruling on one who was killed by a knife to the head during a brawl which he did not instigate, and is he considered a martyr?

The reckoning of people is among the matters of the unseen, and it is not possible to know the reckoning of a specific person now, due to the cessation of revelation. Fighting among Muslims is a grave sin, and martyrdom is not decreed for one killed therein unless the fighting was jihad, or in defense of oneself, property, or honor. So, whoever is killed in defense of his property, religion, blood, or family is a martyr, as stated in the hadith.