Unknown Voice is a guide for the character during a Dream Journey. It guides the character through their adventure and teaches them the answer to their problems. It is not known where it lives, or if it is an existing body.
it is commonly theorized that it is simply a voice the characters make up in their minds.
"Whats the matter Handy? Isn't this what you've always wanted?"
-To Handy at the beginning of his journey
"DreamPuffs, my friend. They sent you and your dog here on a quest to discover who you really are."
-To H8_Seed after he was saved from the hole
"Just be who you were destined to be, NeonPaw-you are loved and useful, not Over Powered as the heartless say."
-to NeonPaw, at the end of her journey
"All the extra power you need is in you already."
-to Lavender Harmony, after she discovered her owner became an anti-brony
"They need you to believe in them, not them to believe you."
-To Star Hunter 's at the end of her journey
"You could always do that, WoodenToaster . But you neglected from letting yourself know it."
-To WoodenToaster, after he accidentally learned Flame Thrower.