In Assassin’s Creed: Brotherhood for the PS3, Xbox 360, and PC, you can unlock the Armor of Brutus for your character to use.
To unlock the Dagger of Brutus, you’ll need to collect all six Keys of Romulus from the Followers Lairs, which are located beneath Prospero da Siena’a Borgia Tower.
This will unlock the Armor of Brutus as well.
