The Siege of Evil

Oh right a bowman, not the most impressive job in the book. But you dont have to stand and fight people bigger than you on a daily basis. You also werent born a mage, figures. You have been pinning the attackers one by one. You arent the best shot, but you kill more than you miss. Not too hard with so many foes down there. But from the corner of your eye you spot something. An attacker managed to sneak through and is going after a mage. Without those guys firepower this battle will not end well. What will you do?