Fortuna Castle 2F
Use your new found power from the anima mercury on the gyro blade. A tutorial will pop up if they are turned on. Smash the metal door and leave. Power up at the divinity statue outside if needs be, then go back to the gallery.
All the orbs have regenerated so they can be collected again. However all the enemies have returned as well. With reinforcements. More scarecrows for easy, whilst they are followed by frosts and a blitz on hard. You can use the gyro blade for massive damage. After the web breaks go back to Main Hall.
Grand Hall 2F
Drop down to the lower floor.
Fortuna Castle 1F
Fortuna Castle Grand Hall 1F
Smash all of the furniture here and the coffin in the centre. There is nothing left to do here so leave via the eastern door.
You can now move the gyro blades in here. To advance all for of the pads in the centre of the hallway need to be occupied by a gyro blade. Two are already in position and a third can be gotten now, but it is easier to wait. Head to the dining room.
Kill all of the knights that are in here. The chairs and the table settings are breakable. Leave from the opposite side and activate the gyro blade. Push it down the corridor, staying behind to protect from the fire balls. Push it all the way into the end, smashing the fireball shooter. The exit is on the right, but the entrance to secret mission 2 is on the end in the wreckage.
First kill all the scarecrows in the room, use the gyro blade if you want to. Then hit the blue switch to open the gate. Next push the gyro blade all the way to the opposite end of the corridor and smash the metal barrier blocking the final gyro blade. The gyro blade will slice through the army of scarecrows that are living here now. Then push both gyro blades onto the glowing plates at the centre of the hallway to open the door. If you got the final blade earlier using one of the two already in position then this can be skipped.
Boss Fight: Bael
In the central courtyard you will encounter the rusulka. These are two demons that appear like naked women. Don't be fooled they are evil but not damaging. After a while the real boss Bael will jump out and try to swallow you. A cut scene will save you from damage the first time. Bael will fire ice shards from his back and jump around a lot and is very mobile for his size. After a while he will jump into a corner and swell to a gigantic size and disappear. The rusulka will return but are more dangerous this time. Bael will return after the rusulka take a certain amount of damage with his swallowing attack. He turns a red colour when knocked down to three bars and will periodically freeze himself. When Bael is defeated you will receive a Rusulka corpse which makes the Devil Bringer glow near secret orb stashes and secret missions. Leave through the door on the side and finish the mission.