Some hint to the Story!
The old people are led by his king: Regius.
He is an very agressive but very very old one. His desire is to rule worlds.. and whole universes.
For that he has many armies which fights for him. He let them train and then send out in couples to run over worlds.
Greed was born with his twin sister Lust. But he was way more brutal and agressive than her. So his father Sin and his mother Saint sent him at a very early age to the military training.
He made out very well, grew up fast and got soon an commander of his own army. So he is very well known by every Antzinako member.
Meanwhile, his sister Lust grew up too but.. she didn't liked the way of her king. And as Greed got sent out, he had to ban her out of his familiy. She was too rebel-like. Now Lust is on her escape, but doomed with her past of being one of the old people.
Greed sweared to kill her the next time they would meet.
After that, Greed and his army was sent out. They conquered many worlds. And it took hundreds of decades. They fought hard enemies, he lost many of his comrades until he had to fight all alone.
Since he was alone, he lost the connection to his own family and people. He was too far away to get mind connection to them, and he fought all alone.. for hundreds of years.
Greed forgot about the time, and never thought of "why am i doing this". He just did what his king ordered, without asking.
But his family and people got extinct by an enemy... more powerfuller than every fighter. An strong illness first defeated the old king, and then, slowly, extincted all the others.
Now there are just very less members left. So even Lust. She now tries to find her brother to stop him. He still kills life beings.. for nothing.