Fear of the Dark
A relatively friendly wizard, the group has only known him through a vision of the past, hundreds of years ago; before Strahd had embraced a dark curse.
When encountered, he was quietly contemplative and eager to hear what Baz, in the form of a young Remmington, had to say. His hands were shaking badly.
He went into the Amber Temple with Strahd several times. The Dusk elves told the adventurers that they lost track of him on one of these trips.
Exethanter was brought to Barovia by Strahd just as the area was being taken. He was Strahd’s longstanding teacher of magic from far away. There is little known about him beyond that, partially as a result of the wizard’s quiet demeanor.