Second Mining Area
There is a divinity statue here if you need to top up. To the left there is a Red Orb cluster behind the wooden planks. There are scarecrows in this are on Son of Sparda mode or higher. To the right there is a lot of Grim Grips to climb until you reach a small platform with the entrance to a tunnel on it. Through the tunnel is some more scarecrows you have to kill. Beyond them, climb the stairs. There is a Vital Star M behind the wood, grab it and carry on to the snowy section.
Fortuna Castle Gate
Follow this top bit until the path drops. There is a red orb atop some stairs to the right and the small, narrow pillars along the way can be smashed. Dropping down introduces a new type of demon, the Frost. Defeat the frosts with the devil bringer. There are more of the narrow pillars down here containing health and if you climb up the big pillars (you need air hike) and use the buster you will find hidden orbs. Carry on across the bridge and you will meet Gloria.
Fortuna Castle Grand Hall
Smash all of the furniture for orbs. The large coffin in the centre is not yet breakable and there is nothing else to do here, save a divinity statue. Head right and enter the hall. From here find the door to the torture chamber, it is the only door on the outside of the corridor except the dining room.
Defeat the demons here, more scarecrows and gladius on hard modes. Break the web and climb the stairs. The pillar here is unbreakable too, so head into the upper level. There are a series of Grim grips to negotiate, they move on hard. Don't hit the spikes on the roof, especially if playing on Heaven/Hell or Hell modes. Hitting the spikes will knock you down and trigger the demons again.
Fortuna Castle 2F
There are magic forcefields blocking almost all of the upper level. The only accessible door is the one on the left of the picture of Sanctus which leads to the central courtyard.
Run across here, there are some frosts to defeat but nothing else.
There is a Vitality Star S above a lamppost here, it is hard to clamber up there but it is worth it. There is a red combat adjudicator here but you can't hurt it. Head up the path above it and leave.
This is the other side of the courtyard. There are more frosts here but it is still as barren as the other side. This leads back to the Hall but on the other side of the sanctus picture.
Fortuna Castle Grand Hall 2F
On the other side there is a switch. Activating this disables the forcefields and allows you proper access to the second floor. There is a holy water and a red orb on top of the pillars above the switch and opposite. To get them you need to snatch them in mid air after a wall jump or an air hike. On the east wall there lies the exit, opposite the door from the upper torture chamber.
There are some scarecrows to kill and lots of red orbs to pick up but nothing of significance. Head through this room to the library.
This snowy corridor is empty apart from a divininity statue. Head into the real library and the door will slam shut. Prepare to meet the new demon, the bianco angelo. Nero thinks that these are allies but they are not. There are four of them in total in this room. There are orbs in the two urns by the side of the gyro blade and in the benches on the second floor. Go through the secret door in the side to pick up the Anima Mercury, which ends the level.