The battlefield north to the Laprix Lord's territory was flooded with the Council of Xylon's army. The long-distance fighters such as their Archers, Mages, and Healers built a small camp at a hillside that bordered the flatlands inside the Laprix's territory.
They used the advantage of their altitude and the lack of hiding spots spread throughout the battlefield to hunt the defenders. The Trilance's forces were not necessarily weaker than the Council of Xylon. If anything, they could only survive this long because they were stronger than the average combatant of the Council's army.
The Valkyria, the elite force of the Valyrians, posed the biggest threat to the Council's army. Their racial trait granted them a minor fire affinity, allowing them to use a wide variety of techniques to overpower their enemies. Even the Valyr Summons were stronger than the average Summon.