Essentially, what Iris did was fill in the blanks for Damien.
He had sufficient information about the Ancient Battlefield itself, but he was lacking in knowledge about the situation between the two forces.
In short, it went something like this:
The number of Nox Demigods versus universal Demigods started off at roughly 10,000 on each side.
When traitors were counted, it changed into a battle of 13,000 against 7,000 or so.
The two bases were stationed at the extreme poles of the battlefield, and thus it was almost impossible to come across the enemy base unless one was intentionally making their way there.
On the universal side, at least a thousand Demigods needed to stay stationed at the base to guard it, and many of those thousand took back-line roles to support those who were battling on the field.
It was still a war.
