- After being released from the jail cells, grab your arsenel from a sack found right before exiting the Cell Block 2nd floor (going into the Library). Make sure you also have your shield!
- Follow the bird from Step 3 slowly. After Brutus is alerted, head back to Richtofen's Laboratory, being careful of the infinite dog spawns.
- After watching the Mob of the Dead ghosts fend of Brutus, a red orb will appear like before. Collect it and head inside to the Laboratory, placing the final orb on the map as before.
- A door will open in the corner of the Laboratory. Enter through and have each player stand on a small pad with yellow lights on the floor at the top of the stairs. You will now enter the Boss Fight.