Varka is the current Grand Master and Knight of Boreas of the Knights of Favonius. Half a year before the Traveler arrived in Mondstadt, he departed on an expedition with the city's elite forces, leaving Jean as the Acting Grand Master in his absence.
Based on other people's remarks about him, Varka is one of the most powerful people in Mondstadt. Tartaglia calls him the "titan of the Knights of Favonius" and hopes to one day face him in combat, while Barbara says that there's nothing to worry about as long as he is leading the expedition.
Varka appears to be jovial and well-liked by the people of Mondstadt. He is rather carefree and often leaves Jean to perform the actual duties required of his position while he goes on expeditions, but Jean does not resent him for it and Kaeya says he appreciates Varka's attitude.
Little is known about Varka's appearance, but Razor's character stories and voicelines suggest he is extremely tall.