Battlecry city was organized by hierarchy with the most powerful Barbarians at the center.
Living on the edge were the low to intermediate-ranked barbarians.
Mad knight Mead charged into this city with 10 teams of holy knights, and the fact that they were already getting killed by these low ranks Barbarians was driving him insane.
Professional Barbarians were not the only ones living in this city but their families as well.
When mad knight Mead yelled "destroy," they all decided to go out in glory.
Even if those Barbarians could escape themselves, their families couldn't. Paired with their battle-thirsty nature and yearning for death, they had a horrifying explosive power when their families were threatened.
A Barbarian's madness sacrificed their life span for a moment of full control with blood from their body. It could drastically increase their fighting power. It was in their nature.