Fear of the Dark
The group only came across him in a vision from hundreds of years ago. Chatting with Exethanter, he spoke more loudly and forcibly than his companion. Perhaps even a little drunk. Of the two, he was the extrovert.
Khazahn was brought from another realm to supplement Exethanter’s teachings of magic to Strahd. He returned frequently to the Amber Temple with and without Strahd. Eventually, he built a tower for himself in Barovia and seemingly retired there.