Cards and heroes can gain levels in War of Omens - while cards have 3 upgrade levels, each next level reducing the cost of buying a card by 1 and you gain those levels by repeatedly selecting the card from packs (4x for 2nd, 20x for 3rd), heroes gain experience levels as you play games with them, and each level rewards you with a small amount of silver and hero card upgrade (card unlocked on hero Lvl. 4, card upgraded to 2nd level on hero Lvl. 8, card upgraded to 3rd level on hero Lvl. 28).
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