Proznanski is a character mentioned in Fallout 4.
Proznanski was a member of Michael Daly's squad before the Great War. Just after the bombs fell, their Vertibird crashed into the Museum of Freedom. After Flaherty and Kanawa, two of his teammates, were killed by scared survivors, Proznanski simply left on his own, never to be seen again, leaving behind his power armor.
Proznanski is mentioned only in Fallout 4.