Can anyone help me? I'm stuck in the garden of illusions, where you have to put the code in for the blue crystal. I can't for the life of me remember anything about a 4 digit code for a blue crystal
Did you do Cassandra's sidequest? You don't need this code to progress, it's just something extra.
There are two switches on two platforms on either side of the area where all the bones are lying around. Activate both of them and you should be able to progress :)
Let me know if you need any further help!