Sergey Urbonas was a Viscount before the Great War.
In June 2072, an assassination attempt was made on his life. Ezra Parker saved him by jumping in front of the bullet, which hit Ezra's silver locket, preventing both of their deaths. 
Sergey Urbonas is mentioned only in the Fallout 4 add-on Far Harbor.
- ↑ Vault 118#Plaques