Oh, and as for Void Demons and other Quantum Shards not part of our main group of characters, we could say only Avatars who were deemed worthy at the moment of bonding by their Shards were granted access to Celestia. In the case of our "bad guy" characters, they may have been worthy at the moment of bonding, but corrupted their Shards after the fact. Those who bonded with a Shard and were immediately deemed unworthy are the ones who first turned into Void Demons, and thus they never came to Celestia. And in some timelines, there are Shards which never found a host and are just waiting to be collected by the Avatars.