Strahd von Zarovich is the lord of Barovia and the master of Castle Ravenloft. He is an immortal vampire, desiring endless power and control. His undead curse is linked to the curse of the land of Barovia that prevents anyone from leaving.
Before he was a vampire, Strahd was simply the lord of the castle Ravenloft. He had a brother, Sergei von Zarovich, who was in love with a woman named Patrina. Strahd was in love with Patrina as well, and wanted her for himself. In anger, Strahd poisoned Sergei and Patrina at their wedding.
Strahd's goal during the Dragon Friends' time in Barovia is to cast a spell that will summon an undead army from another plane. As a component for this spell, he needs to sacrifice the thing he loves most in the world. His trouble is that he has not loved anything since Patrina. He then sees Ireena Kolyana who looks exactly like Patrina and decides that she is Patrina reincarnated. He kidnaps her and keeps her at his castles, where the Dragon Friends go to rescue her.
He rules over Mad Moira and the clan of Moptop clan of deep gnomes. He is very amused by the Dragon Friends attempts to stop him. He has the ability to change from his humanoid form to a swarm of bats.
He can only be defeated by the Name Sword of Sergei von Zarovich. His death by the sword lacks drama, however, because as he is killed he is having uncontrollable diarrhea because of Freezo's Cursed Coins.