Soulfikar
Souflikar was the personal executioner of Mahomet IV during the Ottoman Empire and killed up to three people every day for five years - he killed in total of 5,000 people and the most horrific aspect of his "career" is he never used any instruments of torture and death to do so: he personally strangled each and every victim to death with his bare hands.
As if this was not terrifying enough, if the condemned was a Grand Vizier, it was the custom for Ottoman executioners to race the victims across the royal gardens to the place of execution - if he the Grand Vizier won, he would be set free: yet Soufliker never lost a race and still had the strength to strangle every victim he beat at the race.