Celestial Being
Conviction behind a violent peace
Overall, Celestial Being’s purpose was to unite the world, and eventually, it achieved that goal, though it was only through Celestial Being’s appeared destruction. The world indeed united, only to battle Celestial Being. In a matter of speaking, CB was the sacrifice needed to bring the world together, though that had not been the original intention. But who knows, perhaps Aeolia Schenberg had prepared for his organization to be hated and for that hate to unite separate nation. He, after all, prepared enough to give a secret weapon to the Meisters, Trans-Am, in case someone tried to infiltrate Veda or disrupt his plans.
Not much is known about each member of CB, especially how they came to join the organization. Allelujah was trapped in a ship with limited air supply, back when he was a test subject of the HRL. The likeliest guess is that he was rescued from this ship after Hallelujah had taken over in order to maintain survival, killing the other test subjects who were competing for the air supply. Perhaps he was recruted because of his potential in piloting, nothing is certain. Maybe Sunrise will reveal more to us in season two.
As Allelujah is a part of Celestial Being, it’s not too hard to see why its ideals appealed to Allelujah. Having been used and experimented as a tool for war, he has plenty reasons to want the end of conflicts. He puts CB before himself, willing to kill for those ideals, even though he has never liked fighting or violence.