Here are the riddles needed to get the correct letters. If you solved all of the riddles before, you should be able to do so again, This i the best I can do without directly spoiling the answer for you.
I am the beginning of the end, the end of every place. I am the beginning of eternity, the end of time and space.
What is seen directly before the end of January and February that can’t be seen at the beginning of either month?
On Earth I am dead, though I live on the moon. I am in no crater, but I’m in every bloom. I cannot move on my own, but I’m in each room.
With thieves, I consort… the vilest, in short. I’m quite at ease in depravity, yet all divines need me. Savants couldn’t lose me… for I am the center of gravity. What am I?
NOTE: the riddles do not give the letters in correct order, so you will need to re-arrange them in order to come up with the answer.