[quote=Sapphire]
True but one of her fatal flaws is probably her obsession with humans/mortals. At one point she probably did like Sinbad but Maria changed him for, in Eris's mind, the worst. Your right about playing games, I don't think she gets any satisfaction from crushing others. You also have to remember she gave her word 'as a goddess' to Sinbad. While they don't go into detail about it, she isn't aloud to break that promise. Implying that there could be a number of rules deities from that universe have to follow.
[/quote]

True, that did happen. However, I honestly don't think it's a flaw. If she just went around and killed everyone, what would she have to do? She seems to enjoy tempting people, creating chaos and confusion, but doesn't seem to be the type to kill or torture.
I'm not really sure there ARE any universal rules. I think Eris just cast that spell on herself, and bound herself on purpose, perhaps to make the game more interesting.