Really good design, I hope you will flesh it out with more content. The thematic tie is strong too.
Do you plan to add things to make it a whole game? With for instance, a campaign mode with a map of the realm to conquer or an encyclopedia with all the units discovered.
UI could be improved I believe, for instance by adding icons to specify the troop type on the card and clarify the damage type and life points better than just colours.
Also, the Elephant Archer description could be explained a bit more too, to make it clear that the troop just before it that benefit from its power.
Overall a promising game!

