PvP is a commonly misunderstood subject in Dawn of Fantasy so here are some facts. PvP is accessed by clicking the Pvp button at the upper left hand corner of your army on the world map. The matchmaker pares you with an opponent within a 10% of your army rating. Typical army strengths are between 400 and 800 strength but can go over 3 thousand strength. Building an army camp raises your army strength rating. Having walls built in your town raises your strength rating. Stone walls raise the strength more then wooden palisades. One of the major benefits of pvp is the awarding of Wealth aka crowns with the winner getting 100% and the loser 50% of the battle value. Should the one of the players decide to use the "pay off" button he will lose the units/resources shown but save the rest of this troops and still get the 50% wealth. The winner of the battle gets the opportunity to spend a few minutes looting all the dead units.
The teal colored troops on a map are planned to help defenders of the same race in army vs army combat. Right now they're set to neutral to both sides. Neutral units do not show up in town vs army combat. The minor hamlets on the pvp maps typically hold valuable healing springs/wells in them.
After you've fought a battle you will see a 30 minute timer that keeps your army/town from being attacked. You can purchase more protection time from the ingame shop for Wealth.
DoF features a rock/paper/scissors system over all seen by archers/swords/cav/spears. As with all games balance is rarely "perfect" but the devs in dof continue to balance the game whilst changing how things like armor or weapons work. A few units don't fall into the equation such as macemen, unicorns and ogres. Macemen are excellent against heavily armored troops such cavalry or grandmasters. Unicorns are best used against light troops and archers and they are fast and as zerg like as the elves get. Ogres are best kept away from spears and heavy cav or cross bows. They will however own swords/maces/grandmasters/slayers/marauders and the list goes on. Remember everything has a counter but sometimes asking is simply the best way to discover what it is.