"What happens to an Expanded Realm in the absence of a Regulator?"
"It falls into delirium."
"Expanded Realms possess a colossal amount of energy as a result of the excessive Essence needed to create them. For this energy to remain harmonious, the Bearer who crafted the Realm must be present to Regulate it. Without close Regulation, the flow of energy becomes disrupted. The Essence used to make the sun rise, or the river flow or the rain fall is then channeled inappropriately and so... delirium."
"Clashes of energies sizzle against each other. This leads to what's called Bridge Openings, where, in an attempt to expel some of the uncontrolled energy damaging the Realm, it intentionally opens a Bridge and releases beasts. When these beasts are slain, the Bridges close."
"What the Realm is doing is sacrificing some lifeforms to ensure its own continued existence."