Owari

The mysterious "thirteenth deity", being part of and controlling the Heavenscape, a massive technological fortress that constantly runs simulations on various places and events. They're the ones responsible for providing Chaos with whatever he might need to continue his crusade.

Backstory
* None of this information is currently known to any of the leading characters*

An eternity ago, there lived a civilization whose progress advanced at a vertiginous rate, a world that had survived a thousand hardships and still stood; this made their god very happy.

One fateful day, a new conflict was brought up, and the people started splitting, the deity thought this was just to be another stepping stone in their endless story. They were wrong. Mere days later, the world was devastated, and the last living being decided to take their own life.

Still determined to try again, the god picked up the remains of what she'd built and she started thinking. For seven years and seven days, they thought, they theorized, they simulated, but it always ended in destruction.

Eventually, they ran out of organic materials to keep making their children. They resorted to weep in silence until everything was over, until everything died and they were to take their own life like that last person.

Trivia

 * The name "Owari" literally means end, this comes from her theme "I am end", from the Angelfalse Sakuzyo album.
 * The "Synthesized" Angel title also comes from the same album.