An Evil Entity

The letter said: Dear Jon, I have written this letter, in addition to the one I've placed with the stone, to warn you about a dark entity that has frequently tried to possess the stone. He has chased me across the world and back again. I am too old to outrun him anymore. I hate to make it sound like having the stone is a burden. It's not. Using it the right way will benefit many, as I have done. And I am certain that you will too. Be alert, Jon. This entity can take any form. Your friend, always, Grandpa ----- Jon wasn't sure what to think. An evil entity that wants the stone?