But aether has relatively high attack creatures, unlike earth or gravity. And you don't really need your entire field to be immortal, so quintessences will be enough a lot of the time. And there's also anubis. It's not the same as gravity nymph, draining quanta every turn, or earth/purple nymph, giving more CC every turn, or even water nymph, creating more nymphs every turn. You just don't need to immortalize a creature every turn. No one uses death nymph.