The headmaster of Durmstrang is Professor Igor karkaroff from 24 June- 31 July, 1996. He was a wizard and pure blood; he was a death eater who served lord Voldemort during the first wizard war. After the defeat of his master, he was captured and imprisoned by the Azkaban and turned in several death eaters in exchange of his release.
After his release he went on and became Durmstrang headmaster leading the school delegation to Hogwarts School of witchcraft and wizardry for the 1994 Triward tournament. He flew into panic when his Dark Mark began burn. He fled when he heard about the return of his master and was murder by his former comrades in the summer.