Drogo played a Khal in “A game of thrones”, introduced in 1996. He played the leader of the Dothraki. Dothraki is a tribe of warriors who roam the continent of Essos.
He’s considered as the strongest and most feared of all the khals. Daenerys Targaryen is sold into marriage to him by her elderly brother Viserys in order to secure an alliance with the Dothraki.
Her ensuing relationship with him, and her debut to the brutal world of the Dothraki, prove to be fundamental to her development as both a ruler and a conqueror. Jason Momoa depicts Drogo in the HBO tv adaptation.