Namesakes
Fictional Characters from Books:
1 character
Severus Snape 1997 Harry Potter and the Philosopher's Stone 
Harry Potter Characters:
2 characters
Albus Severus Potter
Severus Snape
Roman and Byzantine Emperors:
1 emperor
Emperor Flavius Valerius Severus (a.k.a. Severus) 306-307
Saints:
4 saints
Saint Severus ?-289
Saint Severus ?-304
Saint Severus ?-455
Saint Severus ?-530