The card battle minigame is kind of a mess. Beastmen have both higher health and much higher damage. So even with numerical advantage, human cards barely hold up.
Also, it may not be so obvious at first glance, but having 5 more HP while opponent has 5 more attack is not balanced at all. Most beastman cards have a 100% chance to one-shot most opposing human cards, while humans can only throw meat into the meat grinder, because their attack is too low to really do anything.
And it's only further exacerbated by the fact that battle mechanic is a simple 1v1 headbutting. Which pretty much nullifies any advantage of higher HP, and only increases the advantage of higher attack.
Edit: Some math:
Golden Berserker with 19 attack will guaranteed kill any human card, even the Diamond Vanguard (the strongest human card). Diamond Berserker with whopping 25 attack, can mince through two Diamond Vanguards and still be alive to kill another card.
And it's not even the strongest card beastmen have. The Revenger is absolutely insane, and can singlehandedly chew through half of human card deck.
If card stats have any ties to the lore strength of the races they represent, I don't know how beastmen haven't steamrolled the entire continent centuries before protagonist spawned into existence.
Edit; Edit:
As if! I had only a couple cards left by the end of that fight. Humans lost their entire army there.
Edit; Edit; Edit: