>The Regi's dots nearly spell out, "AZOTH"
>They all have 7 dots. "It is finished when 7 become 1"
>They consist of all the types Fighting is strong against, except Dark
>Like how the Regi trio represent the Stone Age, Ice Age and Iron Ages, A new Regi rivaling Regigigas will respresent the Dark Ages.

Regigigas was a creator; its counterpart will be a destroyer. The text in the Sealed Chamber was changed in ORAS. It used to read:

"In this cave we have lived.
We owe all to the Pokémon.
But, we sealed the Pokémon away.
We feared it.
Those with courage, those with hope.
Open a door. An eternal Pokémon waits."

It now says:

"Long did we live here in this cave
All thanks to the powerful Pokemon living alongside us
Yet, we sealed that Pokemon away, alone in the dark.
We feared it.
If you have the courage, if you still hold to hope,
Open the door. For beyond it the eternal Pokemon awaits."

"Alone in the dark" is the only significant change here. It isn't talking about Regigigas anymore, it's talking about the new Regi. Oddly, Regigigas appears where you find Regice in ORAS, and is said to visit there. Maybe, since Regice's spot is a tropical island, it's alluding to Alola?