The Impera was the imperial bodyguard brigade, charged with the personal safety of the Emperor of Nilfgaard. Never an empire to take this sort of thing lightly, the brigade numbered five thousand soldiers.
The Witcher 2: Assassins of Kings
Commander Renuald aep Matsen is said to be previously a member.
The Witcher 3: Wild Hunt
There is a card with its name in Nilfgaardian Empire Gwent deck and also Impera Brigade armor.
Trivia
- The brigade might be inspired by Praetorian Guard of Roman Empire.