Robbery from the rich and famous.
That's what they added up to together, Greed told his younger brother with an unusual amount of friendliness, the evening he was having fun finding crimes for every combination of their sins. (Lust went to her room after getting 'prostitution' assigned to her and Greed and 'adultery' to her and Envy, before Greed could tell her what he'd come up with for her and Gluttony.)
Envy, of course, had found some way to turn it into a fight; they weren't friends, they would never be, and only reluctant brothers. Still, the younger Sin crumpled up the paper on which Greed had written the combinations and stuffed it into a handy dry pipe, for reasons which he couldn't quite explain. He never read it again, but went back every ten years or so to check on it, in the same compulsive way he watched over everything that belonged to him. (Perhaps it's something he and Greed have in common, but that doesn't change anything.)
When he went back early, that year Greed left, to rip up the paper and throw it into the stagnant water, he also couldn't quite explain why.
