First off, its a Great game and a nice idea, so i donated to support your hard work. However if useful here's a little bit of feedback...
When finishing the first act and picking your relic it implies that you can either A stay human and get one of the Generic relics or B pick one from the 'curse' based on your deck 'corruption'.
To me the story here is quite compelling i would i suggest that if the player picks B then they are 'Cursed' into that form and don't return to human at the start of the next act.
Using existing assets then in act 2 you would start off as The Slime, Mythical, Beast. Using the existing relics. That way picking the relic based off shielding your character's avatar would be cursed into the female form from then on for all further battles.
Then when completing the 2 act you could then specialize again if your corruption type is still the same. Each of the 3 would have further cursed forms to go with them.
Mythical -> Centaur, Harpy, Mermaid
Beast -> Antro Fox, Wolf, Cat
Slime -> Lamia, Slime girl, Goblin
When picking these forms each would have a relic which changes the game to represent that style of play. For example Centaurs get bonus damage based off there current defense but take more damage to poison.
Maybe the antro fox form could give a card draw and reduce cost when hitting vulnerable targets but have to trash the card from the deck for the battle.
Possibly the Lamia form gain life back when hitting poisoned targets but cannot play cards with shielding?
Obviously this would take a bit more thought and a fair bit of balancing but would create a huge amount of re-playability with some something unique to this style of card game.