"???" and Aphmau will have the same voice actor, however, Aphmau's voice will only appear in trailers. 

Aphmau is the main character of the story, and the character that the player plays as.

Not much can be said for "???", as most of its storyline is non-discloseable and original to the game. This character is present throughout the entire game, however, the protagonist doesn't know of its existence until the final chapter. The character is not a living being, nor is it something that you can physically touch. It exists outside of the realm the game takes place in; some would even say it exists outside of time itself. Many people refer to this character as "the orb", due to its orb-like appearance.

This character will be used as a narrator for the game's introduction scene.

Whether we end up casting a new voice for this character or not depends on how good the auditions are. The current VA is the game's creator, Pink09.

Voice reference:

7:30 - 9:40: https://www.youtube.com/watch?v=dQi5yySccps&list=PL0dTxWJ6ngUI45v2400CfdTZvvbU2oEPX&index=11