How can I increase my Army power?
Army Power is increased by applying upgrades to your regiments, improving Star Levels of your regiments, and improving equipped items (weapon, armor and banner) at your Forge.
Army Power is a measure of combat strength of a regiment. The total sum of each regiment's individual army power is used to rank a Warlord in the All Time Army Power Leaderboard.
In PvP Battle Briefing Screens, you can view the Army Power of your opponent's regiments which is compared to the Army Power of your Top 5 regiments in order to calculate the difficulty (skulls) and rewards.