Overpriced?
Considering the fact that this shield blocks, on average, a little bit more than titanium, this card is fine in terms of pricing.
It does exactly what it says; it prevents the first X damage dealt to you a turn. Not by the first X creatures, the first X damage.
So your opponent has to deal more than 5/8 damage a turn to deal at least one point of damage.
Note that titanium shield blocks about 6-8 damage a turn to my knowledge, in a pure estimate.
This cost is as powerful, and deserves the price of titanium, to my knowledge.
Why shouldn't titanium cost 1 or so, then?
Why aether?
Aether needs a shield that isn't dim shield.
Although I was considering making this a permanent that changes how shields work in life, butttt... complex.
Earth has titanium whilst gravity has armagio.
Aether has the simple "I lose or you lose depending on what elements your using" shield which I hate.