I found the reason immediately..
As for what it was, it could be found on a lot of the corpses.
On their armor, a crest was emblazoned.
The crest symbolized a certain lord from the Asura Kingdom.
That crest was from a place known as the Milbotts territory.
It is a territory that is owned by one of the four major noble families that had a strong military force in the Asura Kingdom.
The soldiers who attacked us came from the faction that ruled over that territory.