I feel like this card would actually give Darkness a form of stalling - if your creatures and total damage output was equal to theirs, and you had no vampire creatures on the field, wouldn't that mean that both you and the opponent would be figuratively 'trading health' each turn until deck out/someone upsets the damage ratio?
P.S. - I wish you did the art for this. It would have been amazing.
Not quite. Let's say you have 20 hp and your opponent has 80 hp.
Let's say you had 5 Shriekers out, doing a total of 40 damage. Your opponent goes down to 40 hp, and you go up to 60 hp.
Let's say your opponent has 2 Ice Dragons, but one of them is frozen, so you have 1 Ice Dragon doing 9 damage. You go down from 60 to 51 hp, and your opponent goes up from 40 to 49 hp.
And this, in a dark mono, is balanced. Just something to deter any Rainbow rushes...