Ruler's Reign/guide

Sword
Enter the moth door. Go down to the bottom then go right. Take the first path going up and interact with the eye. Go south-west and interact with the sword.

Crown
(Sword Effect is needed).

Enter the moth door. Go down to the bottom then go right and through the archway. Go up the stairs and enter the door at the top. Go up again and use the sword on the figure holding the crown. Take the crown from the corpse.

Cloak
Enter the rose door. Go left and enter the building. Take the cloak off the table.

Sceptre
(Sword Effect is needed).

Enter the light green door. Go right and enter the double doors. Use the sword on the woman holding the sceptre then interact with her.

Ending
Go north-east from where you get the Crown Effect and enter the door. Go left and enter the grey door in the middle of the path, which should bring you to a room with a golden bed.

Drop all of your effects in the room by equipping them and pressing 5. After this you'll see the ending screen: Reina is briefly seen standing by a lake before she disappears.