They all ran away and left the fortress empty due to the spirited encouragement of their army commander.
Only the stubborn ones and the ones looting remained behind. They figured that Aeternus wouldn't care about them. They were right. He left the fortress untouched and resumed his journey.
He hadn't seen the end of the serpentine demon.
"What guts," Aeternus exclaimed when he saw the state of the next fortress.
The fortress was also deserted. The snake demon had come here straight from its fortress. It figured that since Aeternus was at its place, he couldn't be here. It initially came to see one of the other two demons in the alliance that was still alive so that they can plan and figure out their situation. He also wanted to know how the fight went.