The ancient Gen'Dai bounty hunter Durge had filled many centuries satisfying his bloodlust for hunting down his targets. However, after he had killed the leader of the Mandalorians, some of these soldiers captured the bounty hunter and exacted their revenge by using his species natural ability to regerenate damage done to their body to torture him almost endlessly. The result of the Mandalorians sadistic acts of punishment helped to further fracture the bounty hunters already fragile mind. As a result of the damage done to him, Durge hid and went into a state of hibernation that lasted for around a millennium.
When he finally awoke fully regenerated Durge had planned his revenge upon the Mandalorians but to his disappointment his enemy had been nearly annihilated by the Jedi. Joining up with Count Dooku, Durge filled his bloodlust by hunting down the Jedi themselves and destroying them.
While on Tatooine, Durge encountered young Boba Fett. Seeing the familar armor worn by the Mandolorians and learning that Boba was the son of the deceased Jango Fett, Durge prepared get his revenge on the descendant of a Mandolorian. Durge's drive to destroy the young Fett would be made even more intense after Boba embarrased him in front of Jabba. Eventually, however, Boba would gain the upper hand and temporarily disable the Gen'Dai bounty hunter when Durge blew up an old ship filled with explosives.
Soure: Star Wars-Boba Fett "Hunted" by Elizabeth Hand