My next arc will feature a chapter that has a few riddles in them. (not going to give any more spoilers than that)

As I am really bad at creating riddles I figured I would do a contest. I will give one riddle here, and the first 3 that PM me with the correct answer get the following reward:

They can come up with a good riddle that will be added to the story. And their name will be added to the thanks in the chapter notes.

Please don't put the answer in the comments. Once I have three winners I will post the answer myself (with a spoiler tag)

This is the riddle for the contest:

I am in everyone.

I am in the earth and in the stone.

I am in life and in death.

I cannot be found in the sky, stars, or mountains.

What am I?

the letter E