The library does not provide tips for the final dungeon. I’ll add some to help you if you are stuck.
Where is Gokuro?
He is inside the owl museum
Where do I find the key to unlock the Gokuro tower?
You get it by saving Luna in the abandoned mansion
How to get in the Gokuro tower?
Go to the path leading to the library, and you will see a symbol of the moon with a crate beside it. Break it to get to the path leading to the tower
How to unblock the ladder in the second room?
Go to the owl museum at night through the regular entrance. Place both statues to the point where the moonlight hits the mat to reveal a new room. Go to the room and throw a bomb on the bell to raise the block in front of the ladder
How to get to the secret room in Gokuro tower?
Push the large owl statue to the sunlight. Needs to be day, obviously
How to use the pattern found in the secret room of Gokuro tower?
Go to the owl village, and all the way to the end. Throw a bomb onto the bell to open the temple. Inside, light up the braziers in the pattern. You can now spawn Gokuro
How to awaken Gokuro?
In the night, move the large owl statue in Gokuro tower to redirect the moonlight to the owl mark on the wall across
How to access the final dungeon?
Bring the green orb from Boko pit and the red orb from the owl furnace to Gokuro. He is inside the temple in owl village. Throw a bomb inside the temple (silver bell) to access the room. He will give you the final orb. Take the three to Marui desert’s central west area. The dungeon is called the sacred owl temple. Use the orbs to open the gate to the temple
Can’t light all braziers in a room/across a gap
You can ignore these for now
You will get a weapon called the owl stick that can spawn fireballs.
I’m missing a dungeon key and cannot progress
There’s one dungeon key beside the top left area of the warp point. Use a bomb to reveal the path.
There’s one key across a gap with a button below a statue. Use a bomb to move the platform, get on it, and then throw the bomb again on the lever across to get to the chest
There’s one key in the top right room beside the warp point, you need a new weapon you get here to access it
There’s the triangle owl key in a robot boss room with yellow rock walls in the centre. This is the room after the double dungeon lock in the east wing of the temple.
I’m unable to use the mirrors inside a specific room
First, make sure you visit the temple in daytime. Second, before using the mirrors, go up a level (to the north-west room using the moving platform) and break a pillar in the sun-door room. Go back down and redirect the sunlight to open the door
What do I do with the bells?
You need to ring them in increasing order of pitch. This means top left first, then bottom right, top right, then the one above the bottom right, and then finally the small bell
What do the 3 levers do?
Use the shadows to align the platforms to form a path above, you’ll need it later
Dark room with a gate
Dig at places you can to reveal pressure plates