Some sources say Shakuni had been insulted when his beloved sister has been married to the blind Kuru king Dhritarashtra and swore to destroy the Kaurava clan. He achieved this by poisoning the mind of his volatile nephew, and influenced Duryodhana into instigating the war with the Pandavas, which resulted in the destruction of the Kauravas. Thus, he is seen by many as the ultimate cause of the destructive Kurukshetra War