Scary palace - hidden alphabets

You are transported into a very scary and mystical place. This is a very old castle, a lot of people once lived in it and now their souls stayed here. They wander through the castle and if anyone misses here, they do not want anyone to let go. There is only one way to get out, if you solve the puzzle, which serves spirits. Now they want you to find all the hidden letters that are hidden from you. All letters are in very unexpected places, you will not be easy, but not much time as we would like! Hurry!