I think this could cost 4 at max. I think its ok, it would be like a Titanium Shield, but requires a 1500 coins fee. And taking any quanta from your pool is usually not a good thing, because it can take the quanta you would soon need. In fact I dont see it being used even in rainbows. If the rainbow can wait a bit, there are much better shields, like Permafrost. If it cant, or dont produce enough quanta, there is the Fog Shield. Even cost 4, I doubt it will be a common card, but cost 5, why to use?