[quote=@Raineh Daze]
<Snipped quote by Zobozun>

It could communicate if it actually wanted to talk to you. It's an asshole, so it doesn't. Plus: canon part of the ending. It's an undead monstrosity that is also basically a pet.
[/quote]

There doesn't seem to be a very large difference between "One-Of-Many cannot speak to anyone but the Spirit-Eater" and "One-Of-Many [i]chooses[/i] not to speak to anyone but the Spirit-Eater".