Cause life needs some better defense IMO.
Because life has so much healing, you can't give life even better shields than it already has... And the imaterial two damage reduction of jade shield is already plenty when combined with heals, bonds or life shards.
A shield like the one that you are suggesting, which would reduce the damage from every creature you get every turn by 2 more (if I understood correctly) would overshadow dusk mantle, fog shield, diamond shield and even dimensional shield in an element like life.
I see your point regarding healing, and I realize that my comment might've been mistaken. However Jade doesn't block much damage unupped, in which case this is better. Upped, it has a really high cost to match. Following the balance for creatures, let's say immaterial is worth 1.5 more quanta in case of shields. Then after 5 turns, Emerald blocks 10 damage per creature for 4*1.5
, and Vitality blocks 20 for 8
. See what I mean?
Dusk, Fog and Dims are shield which make attackers miss, so they are really quite different. About Diamond, that's what I balanced this against. After turns t, unupped, Titanium blocks 2t while this will block t*(t-1)/2; after 5 turns this is just as potent as diamond. In case of upped, it's 3t vs. t(t-1), so after 5 turns this is 1.25 times as potent as diamond. Unupped is 6, with minus 1 cause it is dominated by titanium in the early game (when damage is more crucial). Upped is 10 minus 2 for upgrade. For less quanta Diamond could be put up and protected. And earth does have a powerful heal with Stone Skin.
Consider a general case, where the opponent has 20 damage output from 4 creatures (just a generalization). Then, the damage blocked:
Unupped: Dusk, 50 for 6
; Fog, 40 for 2
; Dim, 60 (only 1 dim played) for 6:chroma; Diamond, 40 for 4
; Vitality, 40 for 5
Upped: Dusk, 50 for 5
; Fog, 40 for 1
; Dim, 60 (only 1 dim played) for 5
; Diamond, 60 for 6
; Vitality, 80 for 8
Excluding Fog (which is just crazy), unupped we have a block to damage ratio where EVERYTHING else is better than Vitality. Upped, it is exactly the same as Dusk and Diamond. So how's it OP?
Yes, you could say he's doing a firestal in a monolife, the difference is that the creatures will live well, this shield is veeeery more weaker than fire shield.
just make a firestal with life, use fire shield and be happy 
Umm, I really don't get your point. If anything, this is OP as it is quite potent at damage reduction.
Hmm, quite interesting, but I guess not new idea. I bet I have already seen similar idea. Anyway, it is thematically ok I only don't like negative attack part which should be reserved for antimatter I suppose.
Well, I haven't, and that's why I posted. And with the mechanic reducing attack upto -1, I think it gets balanced quite a bit. Low attack creatures won't be hurting too much, and then the damage reduction is approxamitely equal to Titanium. The upped might be a bit better than Diamond, which is why the cost is increased.
