No, don't increase the cost, this is already expensive. 3:1 or 5:3 are both horrible quantum-to-damage ratios, even with the immunity to damage spells.
I'm not seeing a whole lot of point to this card... it's like a Skeleton that can't be summoned via death effects. The
synergy would be interesting, so maybe try to think of some ways this can interact with what Air already has? I know it's unoriginal, but the ability could simply be changed to Dive. Or maybe it could automatically Dive every time a death effect is triggered?
I hate to step on your toes with new ideas of my own, but in every situation I can see myself wanting to use some card other than this. The anti-damage-spell effect is decent on its own, it just needs an ability that will provide more interesting combinations.
(Did you see my card idea titled, "Hear Me Roar?" It started out as anti-silence and then I thought it needed to be non-situational so I added Shockwave-on-a-stick, and that ability was a bad idea. That card
really needs a more interesting, balanced ability to give it interesting, balanced combinations. So as I'm saying this to you, I'm reminding myself.
)
Dive is just one idea, brainstorm a bit more and see what you can come up with.
