Charles Martel was a Frankish statesman and military leader who as Duke and Prince of the Franks and Mayor of the Palace, was the facto ruler of Francia from 718 until his death. In 732, the army of the Umayyad Caliphate led by Al Ghhafiqiii met Frankish and Burgundian forces under Charles in an area between the cities of Tours and Poitiers, leading to a decisive, historically important Frankish victory known as the Battle of Tours, ending the "last of the great Arab invasion of France", a military victory termed "brilliant" on the part of Charles. Charles is also considered to be a founding figure of the European Middle Ages. Skilled as an administrator as well as a warrior, he is credited with a seminal role in the emerging responsibilities of the knights of courts, and so in the development of the Frankish system of feudalism.
While Charles is intended to be a great city wall defender, he can serve as an excellent secondary commander due to his damage absorption skill. To get the most from him as soon as possible, DO NOT upgrade him to 2 or 3 stars until you max out his first skill to level 5.