Oras Tar is the greatest city of Eldanor, capitol of the Human race. It provides the last beacon of hope for the people of Eldanor. If Thayne, and the Evils of Ordradeir take Oras Tar, hope for a free world will be lost.
Much like Minas Tirith, the Battle of Oras Tar is the "final straw" for the world of Eldanor as we know it. Two people attack, while two defend, and, as with Lelling, the attackers cannot build units until their 17 minutes are up, and, the defenders should not attack the attackers during this time (it's unfair). The scripts are the same as Lelling, so, once the front gate is destroyed, the attackers will receive reinforcements inside Oras Tar. Also, after 27 minutes, the defenders will each receive reinforcements on the battlefield outside of Oras Tar, providing a good vantage point on the enemy.