Do you prefer armor or attack?

Because they attacked first every round, and the Barbarian's units that are higher up attack first, before the ones below.

As I understand it, the lower-tier Angels of the Swamp creature also attack first, but they just lie there quietly at the end of the battle, unlike the surviving Nagas. So, that's basically the question.

Most likely, it's due to the lack of a counter-attack in the battle between the Nagas.