John Marshal, Hereditary Royal Master-Marshal, magnate in Wiltshire, ruthless capitalised on the chaos of the English civil war between King Stephen and Empress Maude.
Claims to badassery :
(1) Covered the Empress Maude's escape from Winchester, fighting a desperate rearguard action to buy her time to escape. He was ambushed at the Abbey of Wherwell, about ten miles northwest of Winchester. He and an unnamed knight took refuge in the tower of the abbey's church. After refusing to surrender to King Stephen's men, they set the church alight hoping to flush John Marshal out. Marshal still refused to surrender and even threatened to kill the knight with him if he tried to surrender or open the trapdoor of the tower. Eventually Stephen's men left and when Marshal stuck his head out an opening hot, molten lead from the church roof splashed onto his eye - burning him and destroying the eye, literally melting it in the socket. Not only did Marshal not die from sepsis or from the sheer pain such an injury must have caused him, he made it home to his castle at Marlborough - on foot - 25 miles away!
(2) Ruthless = understatement! Soon after this, Marshal found himself in trouble with King Stephen again. Marshal had given up one of his young sons, William (who would later become quite famous in his own regard and quite a badass himself), to Stephen as a hostage, which was a common practice in those times, a sort of "behave yourself because I hold the lives of your kin in my hands" thing. Well, Marshal was undaunted by this and began reinforcing his garrison at Newbury despite Stephen's besieging army and his son as hostage. Angrily, Stephen threatened to hang young William Marshal in front of the castle. John Marshal's reply was to go right ahead as, "I still have the hammer and the anvil with which to forge still more and better sons!" Fortunuately for history, Stephen couldn't bring himself to order young William Marshal's death, and John Marshal had successfully gambled and won.
